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510(k) Data Aggregation
(90 days)
The Revogene® instrument is intended for in vitro diagnostic (IVD) use in performing nucleic acid testing of specific IVD assays in clinical laboratories. Revogene is capable of automated lysis and dilution of samples originating from various clinical specimen types. Revogene performs automated amplification and detection of target nucleic acid sequences by fluorescence-based real-time PCR.
The Revogene is a PCR instrument that automates lysis and dilution of samples, followed by nucleic acid amplification, and detection of target sequences by fluorescence-based real-time PCR. Revogene runs are orchestrated by a combination of software, firmware and instrument control protocol that ensures the adequate combination times and temperatures for sample homogenization and PCR analysis. The Revogene instrument acquires fluorescence signals generated during amplification. The signals are then interpreted by the system using embedded calculation algorithms.
The Revogene requires the use of a 'PIE', i.e., an assay-specific cartridge to which a patient sample is added. The PIE contains the reagents needed to process a sample and to perform a PCR amplification. When the number of assay PIEs to be run is lower than eight, the user fills empty spaces with "MOCK PIE", which are cartridges that simulate the presence of an assay PIE to confer thermal and rotational balance.
The Revogene instrument subject of this Premarket Notification is substantially equivalent to the Revogene instrument cleared under K222779. Meridian is submitting this 510(k) Premarket Notification to implement a photomultiplier tube (PMT) cooling system. This cooling system keeps the PMT environment at a temperature that prevents the appearance of fluorescence glitches, which may stop the Revogene instrument
The provided document is a 510(k) Premarket Notification for a modified medical device, the Revogene instrument. It focuses on the changes made to an existing device (K222779) and its substantial equivalence to the predicate device.
The document does not contain information about acceptance criteria or a detailed study proving the device meets specific acceptance criteria, as one might find in a clinical trial report for an initial device clearance.
Instead, it describes the performance characteristics of functional testing conducted to demonstrate that the modifications (PMT cooling system and Windows 10 upgrade) do not adversely affect the device's performance compared to the predicate. The goal of this submission is to show substantial equivalence, not to establish new performance acceptance criteria.
Therefore, I cannot provide a table of acceptance criteria and reported device performance in the traditional sense, nor can I answer many of your specific questions about study design, sample sizes, ground truth establishment, or expert adjudication, as this information is not present in the provided text.
However, I can extract the available information regarding the functional testing that was performed to support the substantial equivalence claim.
Summary of Available Information on Device Performance and Testing:
1. A table of (implied) acceptance criteria and the reported device performance
The document does not explicitly state quantitative acceptance criteria. Instead, it describes general observations and conclusions from functional testing. The implicit acceptance criterion is "no statistically significant differences" and "operates as expected and yields expected assay results."
Performance Characteristic | Implicit Acceptance Criterion (based on "no statistically significant differences") | Reported Device Performance (Modified Device vs. Predicate) |
---|---|---|
Positivity/Negativity rates of assays | No statistically significant differences | No statistically significant differences observed |
Unresolved result rates of assays | No statistically significant differences | No statistically significant differences observed |
Indeterminate result rates of assays | No statistically significant differences | No statistically significant differences observed |
Mean Ct values of assays | No statistically significant differences | No statistically significant differences observed |
Occurrence of PMT glitches | Reduced occurrence compared to predicate | Activation of PMT cooling system resulted in lower glitch amplitude. No run triggered a PMT error signal upon activation. |
Amplitude of PMT glitches | Reduced amplitude compared to predicate | Activation of PMT cooling system resulted in lower glitch amplitude. No run triggered a PMT error signal upon activation. |
Overall operation with Windows 10 & upgraded software | Operates as expected and yields expected assay results | Operates as expected and yields expected assay results |
2. Sample size used for the test set and the data provenance
- Sample Size for Test Set: The document states "contrived and negative samples in relevant clinical matrix using the following assays...". However, it does not specify the number of samples or runs used for this functional testing.
- Data Provenance: Not explicitly stated, but given it's a regulatory submission by a US company, the testing would typically be conducted according to established protocols within their R&D or QA departments. It is retrospective relative to the design changes, but the testing itself is performed to support the new device version. No information on country of origin of data beyond the manufacturer's location.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- This information is not provided as the testing described is functional performance testing of the instrument, not typically involving expert interpretation of patient samples for ground truth establishment. The "ground truth" here is the expected performance of control samples within the assays.
4. Adjudication method for the test set
- This is not applicable/provided. The testing focuses on the instrument's functional output (e.g., Ct values, glitch occurrence) rather than interpretation of results that would require adjudication.
5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done
- No, this was not done. The device is an instrumentation for clinical multiplex test systems, meaning it processes samples and detects nucleic acids. It does not output images or data that require human readers for interpretation in the way an AI diagnostic imaging device would. Therefore, an MRMC study is not relevant to this type of device or its modifications.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- The device itself is a standalone instrument that performs automated lysis, dilution, amplification, and detection. The "algorithm" here refers to the embedded calculation algorithms within the system that interpret fluorescence signals to determine results. The functional testing described is a form of standalone performance evaluation for the modified instrument. There is no human-in-the-loop component mentioned for the actual nucleic acid detection and interpretation process of the instrument.
7. The type of ground truth used
- The ground truth for the functional testing appears to be based on the expected outcomes from known contrived and negative samples when run with specific IVD assays (Revogene® Strep A, Revogene® Carba C and Revogene® SARS-CoV-2). Essentially, the "ground truth" is the established performance of the assays themselves on control materials, and the instrument must correctly process these, showing no statistical degradation from the predicate.
8. The sample size for the training set
- This information is not provided and is generally not applicable in the context of hardware modifications to an existing IVD instrument as described. The "training set" concept is typically relevant for machine learning algorithms, which are not detailed here beyond "embedded calculation algorithms" that likely leverage established PCR physics and signal processing rather than iterative machine learning training.
9. How the ground truth for the training set was established
- This information is not provided as there is no mention of a traditional "training set" in the machine learning sense. The established performance of the assays with known control materials serves as the reference for evaluating the modified instrument.
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(28 days)
| 21 CFR 864.7280
Factor V Leiden DNA Mutation Detection
Systems
21 CFR 862.2570
The Xpert® FII & FV test is a qualitative in vitro diagnostic genotyping test for the detection of Factor V alleles from sodium citrate or EDTA anticoagulated whole blood. The test is performed on the GeneXpert® Instrument Systems. This test is intended to provide results for Factor II (G20210A) and Factor V Leiden (G1691A) mutations as an aid in the diagnosis in individuals with suspected thrombophilia.
Xpert FII & FV is an automated genotyping test for detecting Factor II and Factor V normal and mutant alleles directly from sodium citrate or EDTA anticoagulated whole blood specimens. Blood specimens are drawn into either sodium citrate or EDTA anticoagulant tubes. Following brief mixing of the sample. 50 uL of the blood sample is transferred to the bottom wall of the Sample opening of the Xpert FII & FV test cartridge. The user initiates a test from the system user interface and places the cartridge into the GeneXpert Instrument System.
The Xpert FII & FV test includes reagents for the detection of Factor II and Factor V normal and mutant alleles. The primers and probes in the Xpert FII & FV test determine the genotype of the Factor II gene (at position 20210) and/or the Factor V gene (at position 1691). The test includes a Sample Processing Control (SPC) to confirm adequate processing and to monitor the presence of inhibitor(s) in the PCR assay. The Probe Check Control (PCC) verifies reagent rehydration, PCR tube filling in the cartridge, probe integrity, and dye stability.
The GeneXpert Instrument Systems family is comprised of GeneXpert Dx System, GeneXpert Infinity System, and GeneXpert System with Touchscreen. The GeneXpert Instrument Systems automate and integrate sample processing, nucleic acid amplification and detection of the target sequences in simple or complex samples using real-time polymerase chain reaction (PCR). The systems consist of an instrument, computer or touchscreen, and preloaded software for running the tests and viewing the results. The GeneXpert Instrument Systems require the use of singleuse disposable cartridges that hold the PCR reagents and host the PCR process. Because the cartridges are self-contained, cross-contamination between samples is minimized.
The GeneXpert Instrument Systems have 1 to 80 modules (depending upon the instrument) that are each capable of performing separate sample preparation and real-time PCR tests. Each module contains a syringe drive for dispensing fluids (i.e., the syringe drive activates the plunger that works in concert with the rotary valve in the cartridge to move fluids between chambers), an ultrasonic horn for lysing cells or spores, and a proprietary I-CORE® thermocycler for performing real-time PCR and detection.
The Xpert FII & FV test performed on the GeneXpert Instrument Systems provides results in approximately 30 minutes.
This document is a 510(k) summary for the Xpert FII & FV diagnostic test, seeking to remove a limitation statement and make minor branding/catalog number changes. It does not contain a study explicitly detailing acceptance criteria and performance against those criteria for the current submission. Instead, it refers to prior clearance (K082118) for the clinical validation supporting the removal of the limitation statement, and asserts that the current changes do not impact performance.
Therefore, the following information is extracted or inferred based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance:
The document explicitly states: "No new performance data were provided in this submission." The basis for substantial equivalence relies on the device being identical to its predicate (K223046) in all technological characteristics relevant to performance. The one significant change (removal of the pediatric patient limitation) is supported by prior clinical validation data (K082118). Since no new performance data or acceptance criteria are presented for this specific submission, this table cannot be fully completed from the provided text.
However, based on the nature of a genetic mutation detection system, typical acceptance criteria would involve analytical sensitivity, analytical specificity, and clinical performance (e.g., concordance with a gold standard). Without the original K082118 submission, specific numerical criteria are not available.
Acceptance Criteria Category | Specific Acceptance Criteria (Inferred/Generic for Genetic Tests) | Reported Device Performance (Implied from Substantial Equivalence and Prior Clearance) |
---|---|---|
Analytical Performance | Precision (reproducibility across runs, lots) | Not explicitly stated in this document; implied to meet prior clearance standards. |
Reproducibility (inter-site, inter-operator) | Not explicitly stated in this document; implied to meet prior clearance standards. | |
Genotyping Accuracy (Concordance with reference method) | Not explicitly stated in this document; implied to meet prior clearance standards, as the test is based on PCR. | |
Limit of Detection | Not explicitly stated in this document; implied to meet prior clearance standards. | |
Interference | Not explicitly stated in this document; implied to meet prior clearance standards. | |
Clinical Performance | Clinical Sensitivity (ability to detect mutation when present) | Not explicitly stated in this document; implied to meet prior clearance standards with sufficient accuracy for diagnosis. |
Clinical Specificity (ability to correctly identify absence of mutation) | Not explicitly stated in this document; implied to meet prior clearance standards with sufficient accuracy for diagnosis. | |
Overall Concordance with Gold Standard | The performance was previously validated in clinical studies (K082118) and deemed acceptable to aid in diagnosis. | |
Robustness/System Performance | SPC/PCC performance | SPC confirms adequate processing and monitors inhibitors; PCC verifies reagent integrity. Performance implicitly meets design requirements. |
2. Sample Size Used for the Test Set and Data Provenance:
- Sample Size: Not explicitly stated in this document. The document refers to "clinical validation data that was submitted and reviewed as part of the original device clearance (K082118)" as the basis for removing the pediatric limitation. The sample size for that original study is not provided here.
- Data Provenance: Not explicitly stated in this document. Given it's a 510(k) for a US market device, it is likely the original clinical validation (K082118) included US data, but this is not confirmed. It refers to "clinical validation data," which typically implies prospective collection of patient samples.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications:
- Not explicitly stated in this document. This level of detail would typically be found in the original clinical validation report (K082118). For genotyping, ground truth is usually established by orthogonal molecular methods, not primarily by expert consensus in the same way as imaging or pathology interpretation.
4. Adjudication Method for the Test Set:
- Not applicable/Not mentioned. For genetic tests where the ground truth is often established through well-defined molecular techniques (e.g., Sanger sequencing or a validated reference method), adjudication by multiple experts in the traditional sense (like for imaging reads) is generally not performed. The ground truth is objective.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:
- No, an MRMC comparative effectiveness study was not done. This type of study is relevant for interpretive tasks (e.g., radiologists reading images) where human performance is being evaluated and compared with and without AI assistance. The Xpert FII & FV is an automated genotyping test; it does not involve human readers interpreting results in the same manner.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, the performance characteristics mentioned (e.g., analytical sensitivity, specificity) for a molecular diagnostic test like the Xpert FII & FV are inherently "standalone" in nature. The device itself performs the assay and provides a qualitative genotype call. The results are automated and interpreted by the diagnostic software.
7. The Type of Ground Truth Used:
- Not explicitly stated in this document, but for genetic tests, the ground truth is typically established by orthogonal molecular methods, such as Sanger sequencing or another highly accurate, validated reference genotyping method. It is not based on expert consensus, pathology, or outcomes data in the way these terms are typically used for imaging or disease diagnosis.
8. The Sample Size for the Training Set:
- Not explicitly stated in this document. The device uses real-time PCR for detection, and while there might be algorithm tuning within the software, the foundational "training" often refers to the design and optimization of primers and probes, and establishment of cut-offs, rather than machine learning on a large training set of clinical samples. The document refers to "clinical validation data" for performance, but not specifically to a training set size for an algorithm.
9. How the Ground Truth for the Training Set was Established:
- Not explicitly stated in this document. This would be part of the original developmental studies for the device (predating K082118). For a PCR-based test, ground truth for developing and optimizing the assay would involve samples with known genotypes confirmed through reference methods.
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(357 days)
| 866.3390
866.3120
862.2570
The cobas liat CT/NG nucleic acid test is an automated, qualitative in vitro nucleic acid diagnostic test that utilizes realtime polymerase chain reaction (PCR) for the direction of Chlamydia (CT) and Neisseria gonorthoeae (NG) nucleic acid in male urine and vaginal swabs, all in cobas PCR Media (Roche Molecular Systems, Inc.).
This test is intended as an aid in the diagnosis of urogenital infections in both symptomatic individuals.
The test is performed on the cobas® liat analyzer which automates and integrates sample purification, nucleic acid amplification, and detection of the target sequence in biological samples using real-time PCR assays. The assay targets both the Cryptic plasmid and 23S rRNA of Chlamydia trachomatis and the pivNG and NGR9 of Neisseria gonorrhoeae. An Internal Control (IC) is also included. The IC is present to control for adequate processing of the target bacteria through steps of sample purification, nucleic acid amplification, and to monitor the presence of inhibitors in the PCR processes.
Here's a summary of the acceptance criteria and study details for the cobas® liat CT/NG nucleic acid test, based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance
The document primarily provides performance metrics rather than explicitly stated acceptance criteria with numerical targets. However, based on the demonstrated performance and the context of a 510(k) submission, the implicit acceptance criteria would be high sensitivity and specificity, indicating reliable detection of CT and NG infections.
Metric (Implicit Acceptance Criteria) | Device Performance - CT (Male Urine) | Device Performance - CT (Vaginal Swabs) | Device Performance - NG (Overall Male Urine) | Device Performance - NG (Overall Vaginal Swabs) |
---|---|---|---|---|
Sensitivity / Positive Percent Agreement (PPA) | 97.3% (92.4%, 99.1%) | 98.2% (93.6%, 99.5%) | 100.0% (97.7%, 100.0%) | 97.7% (92.0%, 99.4%) |
Specificity / Negative Percent Agreement (NPA) | 99.9% (99.7%, 100.0%) | 99.8% (99.5%, 99.9%) | 99.9% (99.6%, 100.0%) | 99.8% (99.6%, 99.9%) |
Reproducibility (Low Positive - 1-2x LoD) | CT: 90.7% | CT: 100% | NG: 99.6% | NG: 100% |
Reproducibility (Moderate Positive - 3-5x LoD) | CT: 96.3% | CT: 100% | NG: 100% | NG: 100% |
Reproducibility (Negative) | CT: 100% | CT: 100% | NG: 100% | NG: 100% |
Analytical Sensitivity (LoD) - CT Serovar D | Urine: 0.085 EB/mL | Vaginal Swab: 0.170 EB/mL | N/A | N/A |
Analytical Sensitivity (LoD) - CT Serovar I | Urine: 0.784 EB/mL | Vaginal Swab: 0.784 EB/mL | N/A | N/A |
Analytical Sensitivity (LoD) - NG Strain 2948 | Urine: 0.250 CFU/mL | Vaginal Swab: 0.500 CFU/mL | N/A | N/A |
Analytical Sensitivity (LoD) - NG Strain 891 | Urine: 0.200 CFU/mL | Vaginal Swab: 0.200 CFU/mL | N/A | N/A |
Invalid Rate (Initial Test) | 0.6% | 0.6% | 0.6% | 0.6% |
Invalid Rate (After Retesting) | 0.2% | 0.2% | 0.2% | 0.2% |
2. Sample Size and Data Provenance
- Clinical Study Test Set (Prospectively collected):
- Total Evaluated Subjects: 4780 (2304 males, 2476 females)
- Male Urine Specimens: 2302 (from 2302 male subjects)
- Vaginal Swabs: 2476 (1240 clinician-collected, 1236 self-collected from 2476 female subjects)
- Data Provenance: Multi-site, prospective study collected at 13 geographically diverse clinical sites across the US.
- Clinical Study Test Set (Archived Specimens - Supplementation):
- Archived Male Urine Specimens: 163
- Archived Vaginal Swabs: 90
- Data Provenance: Prospectively collected samples from a prior clinical trial (K173887).
- Reproducibility Study Test Set: Total 1618 tests (811 vaginal, 807 urine) across 3 external sites. Each panel member tested in triplicate. Low positive (1-2x LoD), moderate positive (3-5x LoD), and negative panel members used.
- Supplemental Precision Study (for CT in urine): 810 evaluable tests on urine panel members (negative, 1x-2x LoD, 3x-5x LoD).
3. Number of Experts and Qualifications for Ground Truth
The ground truth for the clinical study was established using a Patient Infected Status (PIS) or Composite Comparator Algorithm (CCA), which relied on a combination of three FDA-cleared NAATs (NAAT1, NAAT2, and NAAT3). The document does not specify the number of human experts used to establish the ground truth or their qualifications for the clinical study. The "ground truth" was algorithmically derived from the results of the comparator NAATs.
4. Adjudication Method for the Test Set
The adjudication method for the clinical study ground truth (PIS/CCA) followed a rule-based algorithm:
- If NAAT1 and NAAT2 were concordant, that result was the final PIS/CCA.
- If NAAT1 and NAAT2 were discordant, NAAT3 was performed as the tiebreaker.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not done. This study assesses the performance of a diagnostic test (the cobas® liat CT/NG nucleic acid test), which is an automated, qualitative in vitro nucleic acid diagnostic test. It replaced human assessment with an automated process, and the comparison was against a PIS/CCA derived from other reference NAATs, not human readers with and without AI assistance. Therefore, there is no effect size for human readers improving with AI.
6. Standalone (Algorithm Only) Performance
- Yes, a standalone (algorithm only) performance study was done. The entire clinical performance evaluation, reproducibility studies, and analytical studies assess the performance of the cobas® liat CT/NG nucleic acid test itself, which is an automated device performing real-time PCR. It is designed to operate without human intervention beyond sample loading and results interpretation from the automated output.
7. Type of Ground Truth Used
- Clinical Study: Patient Infected Status (PIS) or Composite Comparator Algorithm (CCA) derived from the concordant results of FDA-cleared Nucleic Acid Amplification Tests (NAATs).
- Analytical Studies (LoD, Inclusivity, Specificity, Interference): Known concentrations of specific strains or culture subtypes of bacteria/viruses, spiked into negative clinical specimens.
8. Sample Size for the Training Set
The document does not explicitly describe a separate "training set" for an AI/ML model for the cobas® liat CT/NG nucleic acid test. As a nucleic acid diagnostic test (real-time PCR), it operates based on established biochemical principles and does not typically involve machine learning training in the same way an imaging AI algorithm would. All the data presented is for validation and performance evaluation.
9. How Ground Truth for the Training Set Was Established
Since there is no explicitly mentioned "training set" for an AI/ML model in this context, the method for establishing ground truth for such a set is not applicable or described. The clinical performance is evaluated against a PIS/CCA derived from other NAATs, and analytical performance is against known concentrations.
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(357 days)
| 866.3390
866.3120
862.2570
The cobas® liat CT/NG/MG nucleic acid test is an automated, qualitative in vitro nucleic acid diagnostic test that utilizes real-time polymerase chain reaction (PCR) for the direct detection of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Mycoplasma genitalium (MG) nucleic acid in male urine and vaginal swabs, all in cobas® PCR Media (Roche Molecular Systems, Inc.).
This test is intended as an aid in the diagnosis of urogenital infections in both symptomatic and asymptomatic individuals.
The test is performed on the cobas® liat analyzer which automates and integrates sample purification, nucleic acid amplification, and detection of the target sequence in biological samples using real-time PCR assays. The assay targets both the Cryptic plasmid and 23S rRNA of Chlamydia trachomatis, the pivNG and NGR9 of Neisseria gonorrhoeae, and the 23S rRNA and mgpC of Mycoplasma genitalium. An Internal Control (IC) is also included. The IC is present to control for adequate processing of the target bacteria through steps of sample purification, nucleic acid amplification, and to monitor the presence of inhibitors in the PCR processes.
The provided document describes the cobas® liat CT/NG/MG nucleic acid test, an automated in vitro diagnostic test for the direct detection of Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Mycoplasma genitalium (MG) nucleic acid.
Here's the breakdown of the acceptance criteria and the study proving the device meets them:
1. A table of acceptance criteria and the reported device performance:
The document doesn't explicitly state numerical "acceptance criteria" but rather presents the sensitivity/PPA and specificity/NPA as "performance results." Assuming the performance values achieved in the clinical study are the de facto acceptance criteria for market clearance, the table is compiled from the "Clinical Performance Evaluation" section (Tables 20, 21, and 22).
Specimen Type | Target | Performance Metric | Reported Device Performance (95% CI) |
---|---|---|---|
Male Urine (Total) | CT | Sensitivity/PPA | 97.3% (92.4%, 99.1%) |
CT | Specificity/NPA | 99.9% (99.7%, 100.0%) | |
Male Urine (Total) | NG | Sensitivity/PPA | 100.0% (95.4%, 100.0%) |
NG | Specificity/NPA | 99.9% (99.6%, 100.0%) | |
Male Urine (Total, including archived) | NG | Sensitivity/PPA | 100.0% (97.7%, 100.0%) |
NG | Specificity/NPA | 99.9% (99.6%, 100.0%) | |
Male Urine (Total) | MG | Sensitivity/PPA | 97.1% (93.9%, 98.7%) |
MG | Specificity/NPA | 99.2% (98.8%, 99.5%) | |
Vaginal Swabs (Total) | CT | Sensitivity/PPA | 98.2% (93.6%, 99.5%) |
CT | Specificity/NPA | 99.8% (99.5%, 99.9%) | |
Vaginal Swabs (Total) | NG | Sensitivity/PPA | 95.2% (84.2%, 98.7%) |
NG | Specificity/NPA | 99.8% (99.6%, 99.9%) | |
Vaginal Swabs (Total, including archived) | NG | Sensitivity/PPA | 97.7% (92.0%, 99.4%) |
NG | Specificity/NPA | 99.8% (99.6%, 99.9%) | |
Vaginal Swabs (Total) | MG | Sensitivity/PPA | 95.2% (91.9%, 97.3%) |
MG | Specificity/NPA | 97.8% (97.1%, 98.3%) |
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
- Sample Size for Clinical Study (Test Set):
- Total Subjects: 4852 subjects (2512 females, 2340 males) were enrolled.
- Evaluable Subjects: 4780 evaluable subjects (2304 males, 2476 females).
- Specimens:
- 2302 male urine specimens.
- 1240 clinician-collected vaginal swabs (females).
- 1236 self-collected vaginal swabs (females).
- Archived Specimens: Supplementation included archived specimens from a prior clinical trial (K173887) due to low NG prevalence in prospectively collected male urine and vaginal swabs. The exact breakdown of archived vs. prospective in the final evaluable numbers is not explicitly separated for all analytes, but separate tables are provided for "Archived Male Urine" and "Archived Vaginal Swabs" for NG (which states 163 archived male urine and 90 archived vaginal swabs were used for NG).
- Data Provenance:
- Country of Origin: United States (13 geographically diverse intended use clinical sites across the US).
- Study Design: Multi-site, prospective study, with supplementation from prospectively collected archived specimens for certain analytes.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
The ground truth was established using a Patient Infected Status (PIS) or Composite Comparator Algorithm (CCA) derived from a combination of three FDA-cleared NAATs (NAAT1, NAAT2, and NAAT3).
- Number of Experts: Not applicable, as the ground truth was established by algorithmic comparison of results from FDA-cleared NAATs, not by human expert opinion or adjudication.
- Qualifications of Experts: Not applicable.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
The adjudication method used was a "2+1" algorithm based on FDA-cleared NAATs:
- If NAAT1 and NAAT2 were concordant, that result was taken as the PIS/CCA.
- If NAAT1 and NAAT2 were discordant, NAAT3 was performed as a tiebreaker.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
- MRMC Study: No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done.
- Effect Size of Human Readers with/without AI: Not applicable, as this is an automated diagnostic test that detects nucleic acids, not an AI-assisted interpretation device for human readers.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Standalone Performance: Yes, the clinical performance evaluation (Section 6) assesses the standalone performance of the cobas® liat CT/NG/MG nucleic acid test. The device is described as an "automated, qualitative in vitro nucleic acid diagnostic test," indicating it operates without human "interpretation" of the final result. The study compared the device's output directly against the PIS/CCA ground truth.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)
The ground truth used was a Patient Infected Status (PIS) or Composite Comparator Algorithm (CCA) result. This PIS/CCA was derived from the results of three FDA-cleared Nucleic Acid Amplification Tests (NAATs). This is a form of reference standard derived from multiple laboratory tests.
8. The sample size for the training set
The document does not provide details about a "training set" for the algorithm. This is typical for PCR-based diagnostic devices, which rely on established molecular biology principles and analytical validation rather than machine learning on large training datasets for their core functionality. The performance data presented are for clinical validation against a reference standard.
9. How the ground truth for the training set was established
Not applicable, as no explicit training set for an algorithm is described. The device's underlying technology (real-time PCR) is not typically "trained" in the machine learning sense. Analytical studies (Limit of Detection, Inclusivity, Specificity, Interference) form the basis of validating the reagent and assay design.
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(178 days)
21 CFR 862.2570, Real Time Nucleic Acid Amplification
System, OOI. |
| Classification
Advisory
The Xpert Xpress CoV-2/Flu/RSV plus test, performed on the GeneXpert Xpress System, is an automated multiplexed real-time reverse transcriptase polymerase chain reaction (RT-PCR) test intended for use in the simultaneous in vitro qualitative detection and differentiation of severe acute respiratory syndrome coronavirus (SARS-CoV-2), influenza A, influenza B, and/or respiratory syncytial virus (RSV) viral RNA in nasopharyngeal swab anterior nasal swab specimens collected from individuals with signs and symptoms of respiratory tract infection. Clinical signs and symptoms of respiratory tract infection due to SARS-CoV-2, influenza B, and RSV can be similar.
The Xpert Xpress CoV-2/Flu/RSV plus is intended for use in the differential detection of SARS-CoV-2, influera A, influenza B, and/or RSV RNA and aids in the diagnosis of COVID-19, influenza, and/or RSV infections if used in conjunction with other clinical and epidemiological information, and laboratory findings. SARS-CoV-2, influenza A. influenza B, and RSV viral RNA are generally detectable in nasopharyngeal swab and anterior nasal swab specimens during the acute phase of infection.
Positive results are indicative of the identified virus, but do not rule out bacterial infection or co-infection with other pathogens not detected by the test. The agent (s) detected by the Xpert Xpress CoV-2/Flu/RSV plus test may not be the definite cause of the disease.
Negative results do not preclude SARS-CoV-2, influenza A virus, and/or RSV infection. The results of this test should not be used as the sole basis for treatment or other patient management decisions.
The Xpert Xpress CoV-2/Flu/RSV plus test is an automated in vitro diagnostic test for the simultaneous qualitative detection and differentiation of SARS-CoV-2. Flu A. Flu B. and RSV viral RNA in nasopharyngeal swab (NPS) and anterior nasal swab (NS) specimens collected from individuals showing signs and symptoms of respiratory viral infection.
The Xpert Xpress CoV-2/Flu/RSV plus test is performed on GeneXpert Xpress System, which consist of a GeneXpert IV instrument that executes sample preparation, nucleic acid amplification and real-time fluorescent signal detection for the tests, and a GeneXpert Hub with preloaded GeneXpert Xpress software for running the tests and viewing the test results. The GeneXpert Hub accessory integrates the computer, touchscreen monitor and barcode scanner. Each of the GeneXpert modules in the GeneXpert IV instrument can perform independent sample preparation and testing. The GeneXpert Xpress System requires the use of single-use disposable cartridges that hold the RT-PCR reagents and host sample purification, nucleic acid amplification, and detection of the target sequences. Because the cartridges are self-contained, cross-contamination between samples is minimized.
The Xpert Xpress CoV-2/Flu/RSV plus test cartridge includes reagents for the detection of SARS-CoV-2, Flu A, Flu B and RSV viral RNA from NPS and NS specimens. The primers and probes in the Xpert Xpress CoV-2/Flu/RSV plus test are designed to amplify and detect unique sequences in the genes that encode the following proteins: SARS-CoV-2 nucleocapsid (N), SARS-CoV-2 envelope (E), SARS-CoV-2 RNA-dependent RNA polymerase (RdRP), influenza A matrix (M), influenza A basic polymerase (PB2), influenza A acidic protein (PA), influenza B matrix (M), influenza B non-structural protein (NS), and the RSV A and RSV B nucleocapsid. A Sample Processing Control (SPC) and a Probe Check Control (PCC) are also included in the cartridge utilized by the GeneXpert Xpress System. The SPC is present to control for adequate processing of the sample and to monitor for the presence of potential inhibitor(s) in the RT-PCR reaction. The SPC also ensures that the RT-PCR reaction conditions (temperature and time) are appropriate for the amplification reaction and that the RT-PCR reagents are functional. The PCC verifies reagent rehydration, PCR tube filling, and confirms that all reaction components are present in the cartridge including monitoring for probe integrity and dye stability.
The Xpert Xpress CoV-2/Flu/RSV plus test is designed for use with NPS or NS specimens collected with nylon flocked swabs and placed into viral transport medium (VTM), Universal Transport Medium (UTM), or eNAT®. The ancillary specimen collection kits, swabs and transport media validated for use with the Xpert Xpress CoV-2/Flu/RSV plus test include:
- Nasopharyngeal Sample Collection Kit for Viruses
- Copan UTM® 3C057N (Flexible Minitip Flocked Swab with UTM® Medium O without Beads)
- Copan eNAT® Molecular Collection and Preservation Medium P/N 6U074S01 о (Flexible Minitip Flocked Swab with eNAT® Medium)
- Becton Dickinson Universal Viral Transport Kit P/N 220531 (Flexible Minitip o Flocked Swab with UVT Medium)
- Nasal Sample Collection Kit for Viruses
- Copan UTM® 3C064N (Regular Flocked Swab with UTM® Medium without O Beads)
- Copan eNAT® Molecular Collection and Preservation Medium P/N 6U073S01 O (Regular Flocked Swab with eNAT® Medium)
- Alternatively, swabs and transport media can be obtained separately: ●
- Nylon flocked swab (Copan P/N 502CS01, 503CS01) o
- Viral transport medium, 3 mL (Copan P/N 330C, 3C047N, BD Universal O Transport Medium, Remel M4RT or Remel M5)
These ancillary reagents allow NPS and NS specimens from patients to be collected, preserved and transported to laboratory prior to analysis with the Xpert Xpress CoV-2/Flu/RSV plus test.
The provided document is a 510(k) Summary for the Cepheid Xpert Xpress CoV-2/Flu/RSV plus test. It details the performance studies conducted to demonstrate substantial equivalence to a predicate device. Here's a breakdown of the acceptance criteria and study proving the device meets them, based on the provided text:
Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly demonstrated through the reported performance in both analytical and clinical studies, aiming for high levels of agreement with established methods. The summarized performance data serves as the proof that the device meets these (implied) acceptance criteria.
Table of Acceptance Criteria and Reported Device Performance:
Since explicit acceptance criteria values (e.g., "PPA must be >= 95%") are not explicitly stated in the provided text as separate criteria, I will infer them from the reported strong performance and the nature of a 510(k) submission, where substantial equivalence to a predicate device is the goal. The reported performance is the validation that it meets the expected performance for such a device.
Performance Metric Category | Specific Metric (Target) | Acceptance Criteria (Implied / Goal) | Reported Device Performance (Xpert Xpress CoV-2/Flu/RSV plus) |
---|---|---|---|
Analytical Sensitivity (Limit of Detection - LoD) | LoD for various viral strains (copies/mL, TCID50/mL, FFU/mL, IU/mL, CEID50/mL) in NPS/NS matrix | Lowest concentration for each strain at which 95% of replicates yield a positive result. | NPS Matrix: SARS-CoV-2: 138 copies/mL (NATtrol), 94 IU/mL (WHO). Flu A: 0.007-0.44. Flu B: 2.4-12.9. RSV: 0.17-0.37. |
NS Matrix: SARS-CoV-2: 64 copies/mL, 143 IU/mL. Flu A: 0.0028-0.49. Flu B: 2.41-26.3. RSV: 0.22-0.4. (All verified with 20 replicates per virus/lot). | |||
Analytical Reactivity (Inclusivity) | Detection of diverse strains within each target (SARS-CoV-2, Flu A, Flu B, RSV A, RSV B) | 100% detection of tested strains at ~3x LoD. In silico: high percentage exact matches/1 mismatch. | In silico: SARS-CoV-2 E: 100%, N2: 99.9%, RdRP: 100% (total 1.7e5 RNA copies/mL) & RSV A (>1.7e6 RNA copies/mL). SARS-CoV-2 inhibited Flu B (>1e5 RNA copies/mL). Issues resolved by reducing interfering virus concentration. No other competitive interference. |
Potentially Interfering Substances | No impact on test performance by substances found in respiratory specimens. | 8/8 replicates correctly identified for positive samples (viruses at 3x LoD) and negative samples. | Interference Observed & Resolved: FluMist, human PBMC, snuff, Zicam showed interference at high concentrations for some targets. Inhibitory effects not observed at lower or adjusted concentrations. All other substances (Table 13) showed no interference. |
Carryover Contamination | No contamination from high positive to negative samples. | All 40 positive samples correctly detected. All 42 negative samples correctly detected. | All 40 positive samples (high Flu B and SARS-CoV-2) were correctly reported as positive for their respective targets. All 42 negative samples were correctly reported as negative. No carry-over contamination observed. |
Reproducibility | Consistent results across sites, operators, and days for various sample concentrations. | High percent agreement across operators and sites for negative, low positive, and moderate positive samples. Low coefficient of variation (CV%) for Ct values. | Clinical Agreement: Negatives: 100%. SARS-CoV-2 Low/Mod Pos: 100%. Flu A Low Pos: 97.8% (88/90). Flu A Mod Pos: 100%. Flu B Low Pos: 97.8%. Flu B Mod Pos: 100%. RSV Low/Mod Pos: 100%. |
Ct Value Variability: Total CV% for analytes ranged from 0.9% to 3.6%. | |||
Clinical Performance (NPS) | High Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) compared to comparator. | PPA and NPA (typically >90-95% for 510(k) submissions) relative to US FDA-cleared molecular panels. | SARS-CoV-2: PPA 98.7% (96.6-99.5 CI), NPA 98.5% (97.7-99.0 CI). |
Flu A: PPA 99.1% (96.6-99.7 CI), NPA 98.5% (97.9-99.0 CI). | |||
Flu B: PPA 96.6% (88.5-99.1 CI), NPA 99.9% (99.7-100.0 CI). | |||
RSV: PPA 97.8% (92.4-99.4 CI), NPA 100% (99.7-100.0 CI). | |||
Clinical Performance (NS) | High Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) compared to comparator. | PPA and NPA (typically >90-95% for 510(k) submissions) relative to US FDA-cleared molecular panels. | SARS-CoV-2: PPA 98.4% (96.2-99.3 CI), NPA 99.3% (98.7-99.6 CI). |
Flu A: PPA 97.6% (94.6-99.0 CI), NPA 98.9% (98.3-99.2 CI). | |||
Flu B: PPA 100% (89.9-100.0 CI), NPA 99.9% (99.6-100.0 CI). | |||
RSV: PPA 97.0% (91.6-99.0 CI), NPA 99.9% (99.6-100.0 CI). | |||
Non-Determinate Rate (Wastage/Invalid) | Low initial and final non-determinate rates. | Low percentage (e.g., |
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The Panther Fusion system is a class II exempt device under 21CFR 862.2570 that has product code OOI.
The Panther Fusion system is a class II exempt device under 21CFR 862.2570 that has product code OOI.
The Panther Fusion® SARS-CoV-2/Flu A/B/RSV assay is a fully automated multiplexed real-time polymerase chain reaction (RT-PCR) in vitro diagnostic test intended for the qualitative detection and differentiation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (Flu A), influenza B virus (Flu B), and respiratory syncytial virus (RSV). Nucleic acids are isolated and purified from nasopharyngeal (NP) swab specimens and anterior nasal (AN) swab specimens obtained from individuals exhibiting signs and symptoms of a respiratory tract infection. Clinical signs and symptoms of respiratory viral infection due to SARS-CoV-2, influenza, and RSV can be similar. This assay is intended to aid in the differential diagnosis of SARS-CoV-2, Flu A, Flu B, and RSV infections in humans and is not intended to detect influenza C virus infections.
Nucleic acids from the viral organisms identified by this test are generally detectable in NP and AN swab specimens during the acute phase of infection and identification of specific viral nucleic acids from individuals exhibiting signs and symptoms of respiratory tract infective of the presence of the identified virus and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.
Positive results do not rule out coinfection with other organism(s) detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay may not be the definite cause of disease. Negative results do not preclude SARS-CoV-2, influenza A virus, influenza B virus, or RSV infections. This assay is designed for use on the Panther Fusion system.
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is classified as a Class II in vitro diagnostic device per 21 CFR 866.3981 and has product code QOF. The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is designed for use on the fully automated Panther Fusion System.
The Panther Fusion system is a class II exempt device under 21CFR 862.2570 that has product code OOI.
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a multiplex real-time reverse transcriptase PCR (RT-PCR) in vitro diagnostic test developed for use on the fully automated Panther Fusion system to detect and differentiate SARS-CoV-2, influenza A, influenza B, and respiratory syncytial virus (RSV) directly from nasopharyngeal and anterior nasal swab specimens, from individuals exhibiting signs and symptoms of a respiratory tract infection.
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay involves the following steps: sample lysis, nucleic acid capture and elution transfer, and multiplex RT-PCR where analytes (when present) are simultaneously amplified, detected and differentiated. Nucleic acid capture and elution takes place in a single tube on the Panther Fusion system. The eluate is transferred to the Panther Fusion system reaction tube containing the assay reagents. Multiplex RT-PCR is then performed for the eluted nucleic acid on the Panther Fusion system.
Sample lysis, nucleic acid capture, and elution: Prior to processing and testing on the Panther Fusion system, specimens are transferred to a Specimen Lysis Tube containing specimen transport media (STM). Alternatively, samples can be collected with the RespDirect Collection kit which contains enhanced specimen transport media (eSTM). STM and eSTM lyse the cells, release target nucleic acid and protect them from degradation during storage. The Internal Control-S (IC-S) is added to each test specimen and controls via the working Panther Fusion Capture Reagent-S (wFCR-S). The IC-S is the reagent used to monitor specimen processing, amplification and detection. Magnetic particles with covalently bound oligonucleotides mediate the nucleic acid capture. Capture oligonucleotides hybridize to nucleic acid in the test specimen. Hybridized nucleic acid is then separated from the lysed specimen in a magnetic field. Wash steps remove extraneous components from the reaction tube. The elution step elutes purified nucleic acid. During the nucleic acid capture and elution step, total nucleic acid is isolated from specimens.
Elution transfer and RT-PCR: During the elution transfer step, eluted nucleic acid is transferred to a Panther Fusion tube already containing oil and reconstituted mastermix. Target amplification occurs via RT-PCR. A reverse transcriptase generates a DNA copy of the target sequence. Target specific forward and reverse primers and probes then amplify targets while simultaneously detecting and discriminating multiple target types via multiplex RT-PCR. The Panther Fusion system compares the fluorescence signal to a predetermined cut-off to produce a qualitative result for the presence or absence of the analyte. The positive result for each analyte will be accompanied by the cycle threshold (Ct value).
Here's a breakdown of the acceptance criteria and the study details for the Hologic Panther Fusion SARS-CoV-2/Flu A/B/RSV assay, based on the provided document:
Acceptance Criteria and Device Performance
The document describes the performance of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay in detecting SARS-CoV-2, Flu A, Flu B, and RSV in prospectively collected Anterior Nasal (AN) swab specimens in RespDirect eSTM.
Table of Acceptance Criteria (Implicit) and Reported Device Performance
While explicit acceptance criteria (e.g., minimum PPA/NPA values) are not stated, the document presents the observed Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) with their 95% Confidence Intervals. These values are implicitly the performance targets for the assay.
Target Virus | Prevalence (%) | PPA (% (95% CI)) | NPA (% (95% CI)) |
---|---|---|---|
Prospective Study (n=1021 evaluable AN swab specimens) | |||
SARS-CoV-2 | 10.8 | 99.1 (95.0, 99.8) | 99.0 (98.1, 99.5) |
Flu A | 1.1 | 100 (74.1-100) | 99.9 (99.4, 100) |
Flu B | 0.6 | 83.3 (43.6, 97.0) | 99.8 (99.3, 99.9) |
RSV | 0.1 | 100 (20.7, 100) | 99.9 (99.4, 100) |
Enrichment Study (n=205 evaluable AN swab specimens) | |||
Flu A | N/A | 97.2 (90.3-99.2) | 93.2 (87.6-96.4) |
Flu B | N/A | 97.8 (88.4-99.6) | 99.4 (96.5-99.9) |
RSV | N/A | 98.4 (91.3-99.7) | 95.8 (91.2-98.1) |
Study Information
2. Sample Size Used for the Test Set and Data Provenance
- Prospective Study:
- Sample Size: 1021 evaluable anterior nasal (AN) swab specimens.
- Data Provenance: Prospective, multicenter study conducted in the US between January 2023 and May 2023 at nine participating medical facilities.
- Enrichment Study (Supplemental Clinical Data for Low Prevalence Analytes):
- Sample Size: 205 evaluable anterior nasal (AN) swab specimens.
- Data Provenance: Enrichment phase of the study, conducted in the US between October 2023 and February 2024 at six participating medical facilities. The specimens were from individuals with a positive standard of care (SOC) test result for Flu A, Flu B, and/or RSV. All were frozen prior to testing.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number or qualifications of experts used to establish the ground truth. Instead, it refers to:
- For SARS-CoV-2: A composite comparator algorithm (CCA) consisting of up to three highly sensitive US FDA EUA SARS-CoV-2 molecular tests.
- For Flu A, Flu B, and RSV: A US FDA-cleared molecular Flu A/B/RSV assay (in the prospective study) and a U.S. FDA-cleared molecular Flu A/B/RSV assay (in the enrichment study).
- For the enrichment study, initial selection was based on a positive standard of care (SOC) test result for Flu A, Flu B, and/or RSV.
4. Adjudication Method for the Test Set
- For SARS-CoV-2 in the prospective study: A Composite Comparator Algorithm (CCA) was used. A final CCA result was assigned when two of the three composite comparator assays were in concordance.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study involving human readers and AI assistance was not done. This study is for an in vitro diagnostic (IVD) assay (a molecular test), not an AI-powered diagnostic imaging device.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, this study represents a standalone performance evaluation of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay. The assay itself is an automated molecular diagnostic test on the Panther Fusion system, and its performance was evaluated against comparator methods (other molecular tests or algorithms), not against human interpretation of its outputs in a clinical setting for diagnostic aid.
7. The Type of Ground Truth Used
- SARS-CoV-2: Composite comparator algorithm (CCA) based on multiple FDA EUA molecular tests.
- Flu A/B/RSV: US FDA-cleared molecular Flu A/B/RSV assay.
- Enrichment Study (Flu A/B/RSV): US FDA-cleared molecular Flu A/B/RSV assay, and initial selection based on positive Standard of Care (SOC) test results.
This represents a reference standard method ground truth, where another established diagnostic test is used as the benchmark.
8. The Sample Size for the Training Set
The document does not provide information on a specific "training set" sample size for algorithm development. The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a real-time RT-PCR in vitro diagnostic test, not a machine learning or AI algorithm in the context of typical training/validation splits. Its development would involve analytical studies and design verification, but not typically a "training set" in the same sense as an AI model. The provided clinical data are for performance evaluation.
9. How the Ground Truth for the Training Set Was Established
As noted in point 8, the concept of a "training set" with established ground truth in the context of AI models is not directly applicable here. The assay's performance characteristics (e.g., limit of detection, analytical reactivity) are established through various analytical studies (bench studies), not through a "training set" with a clinical ground truth. The clinical studies described are for validation and performance assessment, not for training an algorithm.
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(76 days)
The Panther Fusion system is a class II exempt device under 21CFR 862.2570 that has product code OOI.
The Panther Fusion system is a class II exempt device under 21CFR 862.2570 that has product code OOI.
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a fully automated multiplexed real-time polymerase chain reaction (RT-PCR) in vitro diagnostic test intended for the qualitative detection and differentiation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (Flu A), influenza B virus (Flu B), and respiratory syncytial virus (RSV). Nucleic acids are isolated and purified from nasopharyngeal (NP) swab specimens and anterior nasal (AN) swab specimens obtained from individuals exhibiting signs and symptoms of a respiratory tract infection. Clinical signs and symptoms of respiratory viral infection due to SARS-CoV-2, influenza, and RSV can be similar. This assay is intended to aid in the differential diagnosis of SARS-CoV-2, Flu A, Flu B, and RSV infections in humans and is not intended to detect influenza C virus infections.
Nucleic acids from the viral organisms identified by this test are generally detectable in NP and AN swab specimens during the acute phase of infection and identification of specific viral nucleic acids from individuals exhibiting signs and symptoms of respiratory tract infective of the presence of the identified virus and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions. Positive results do not rule out coinfection with other organism(s) detected by the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay may not be the definite cause of disease. Negative results do not preclude SARS-CoV-2, influenza A virus, influenza B virus, or RSV infections. This assay is designed for use on the Panther Fusion system.
The Hologic RespDirect Collection Kit is cleared for NP swab specimens only for testing with the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay.
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is classified as a Class II in vitro diagnostic device per 21 CFR 866.3981 and has product code QOF. The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is designed for use on the fully automated Panther Fusion System.
The Panther Fusion system is a class II exempt device under 21CFR 862.2570 that has product code OOI.
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay is a multiplex real-time reverse transcriptase PCR (RT-PCR) in vitro diagnostic test developed for use on the fully automated Panther Fusion system to detect and differentiate SARS-CoV-2, influenza A, influenza B, and respiratory syncytial virus (RSV) directly from nasopharyngeal and anterior nasal swab specimens, from individuals exhibiting signs and symptoms of a respiratory tract infection.
The Panther Fusion SARS-CoV-2/Flu A/B/RSV assay involves the following steps: sample lysis, nucleic acid capture and elution transfer, and multiplex RT-PCR where analytes (when present) are simultaneously amplified, detected and differentiated. Nucleic acid capture and elution takes place in a single tube on the Panther Fusion system. The eluate is transferred to the Panther Fusion system reaction tube containing the assay reagents. Multiplex RT-PCR is then performed for the eluted nucleic acid on the Panther Fusion system.
Here's a breakdown of the acceptance criteria and the study details for the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay, based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance
Target Virus | Acceptance Criteria (Implicit for New Specimen Type) | Reported Performance (Prospective AN Swab) PPA % (95% CI) [n/N] | Reported Performance (Prospective AN Swab) NPA % (95% CI) [n/N] | Reported Performance (Retrospective AN Swab) PPA % (95% CI) [n/N] | Reported Performance (Retrospective AN Swab) NPA % (95% CI) [n/N] |
---|---|---|---|---|---|
SARS-CoV-2 | Comparable to predicate device; high PPA/NPA expected for molecular tests. | 94.8 (90.1, 97.3) [146/154] | 98.8 (98.0, 99.3) [1023/1035] | N/A (Not reported separately) | N/A (Not reported separately) |
Flu A | Comparable to predicate device; high PPA/NPA expected for molecular tests. | 91.8 (80.8, 96.8) [45/49] | 99.6 (99.0, 99.8) [1135/1140] | 97.9 (89.1, 99.6) [47/48] | 98.4 (94.4, 99.6) [123/125] |
Flu B | Comparable to predicate device; high PPA/NPA expected for molecular tests. | 66.7 (20.8, 93.9) [2/3] | 99.7 (99.3, 99.9) [1183/1186] | 97.2 (90.3, 99.2) [69/71] | 100 (96.4, 100) [102/102] |
RSV | Comparable to predicate device; high PPA/NPA expected for molecular tests. | 94.4 (74.2, 99.0) [17/18] | 99.8 (99.4, 100) [1169/1171] | 98.0 (89.5, 99.6) [49/50] | 99.2 (95.5, 99.9) [122/123] |
Note on Acceptance Criteria: The document explicitly states the goal is to demonstrate "comparable" performance to the predicate device (which uses an NP swab) for the new anterior nasal (AN) swab specimen type. While specific numerical acceptance criteria (e.g., "PPA must be >X%") are not provided in this summary, the reported performance metrics (PPA, NPA, and their confidence intervals) are presented to demonstrate this comparability and overall effectiveness for diagnostic use, as typical for molecular assays expanding their indications. The high NPA values for all targets indicate good specificity, and generally high PPA values indicate good sensitivity, especially when considering the confidence intervals. The lower PPA for Flu B in the prospective study was addressed and supported by the retrospective study, which showed strong performance.
2. Sample Sizes Used for the Test Set and Data Provenance
-
Prospective Clinical Study (Anterior Nasal Swab):
- Sample Size: 1,268 individuals were enrolled. 1,230 AN swab specimens were tested, resulting in 1,189 evaluable specimens for analysis (not all evaluable for all analytes).
- Data Provenance: Prospective, multicenter study conducted in the US. Specimens were collected from individuals attending nine participating medical facilities in the US during the 2022-2023 respiratory infection season.
-
Retrospective Clinical Study (Anterior Nasal Swab - Supplement for Flu B and RSV):
- Sample Size: 175 preselected retrospective specimens.
- Data Provenance: Retrospective. The origin country is not explicitly stated but is implied to be related to the US context from the prospective study.
-
Analytical Studies (Reprocessing from K222736):
- Sample Size: Not explicitly stated as "sample size" for each analytical study detail, but refers to the number of replicates/conditions tested for LOD, inclusivity, exclusivity, etc. For example, Flu B LoD confirmation involved 28 replicates per panel.
- Data Provenance: Already existing data from the previous 510(k) submission (K222736) using Nasopharyngeal (NP) swabs, reprocessed with the updated software.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications
The document does not mention the use of experts to establish ground truth for the clinical test sets. Instead, the ground truth was established by comparing the candidate device's results to reference molecular assays:
- SARS-CoV-2: A composite comparator algorithm (CCA) consisting of up to three highly sensitive US FDA EUA SARS-CoV-2 molecular tests. A final CCA result was assigned when two of the three comparator assays were in concordance.
- Flu A, Flu B, and RSV: A US FDA-cleared molecular Flu A/B/RSV assay.
4. Adjudication Method for the Test Set
- SARS-CoV-2 Ground Truth: For SARS-CoV-2, a composite comparator algorithm (CCA) was used. A final CCA result was assigned when "two of the three composite comparator assays were in concordance." This effectively acts as an adjudication method where agreement among a majority of reference tests determines the ground truth.
- Flu A, Flu B, RSV Ground Truth: For Flu A, Flu B, and RSV, a single "US FDA-cleared molecular Flu A/B/RSV assay" was used as the comparator method. There's no mention of an adjudication process among multiple comparators for these targets.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not explicitly mentioned or conducted. This type of study is more common for imaging devices or diagnostics that involve subjective interpretation by human readers. This device is an automated molecular diagnostic assay, where the output is objective (positive/negative, Ct value).
6. Standalone (Algorithm Only) Performance Study
- Yes, the performance data presented (PPA, NPA) directly reflects the standalone performance of the Panther Fusion SARS-CoV-2/Flu A/B/RSV assay. It is compared to a ground truth established by other molecular tests, without human interpretation of the assay's output influencing the performance metrics. The assay itself is automated, so its performance is inherently "algorithm only" in the context of generating results.
7. Type of Ground Truth Used
- Molecular Comparator Assays: The ground truth for the clinical test sets (both prospective and retrospective) was established using other legally marketed and highly sensitive molecular diagnostic tests.
- For SARS-CoV-2: A composite of up to three US FDA EUA SARS-CoV-2 molecular tests.
- For Flu A, Flu B, RSV: A US FDA-cleared molecular Flu A/B/RSV assay.
8. Sample Size for the Training Set
- The document does not explicitly state the sample size used for the training set. This submission focuses on the validation of an existing assay with a new specimen type (anterior nasal swab) and a software update (Adaptive Crosstalk Correction). The original development and training data for the core assay (K222736) would have been described in that prior submission, but are not detailed here for this specific submission's scope. The mention of "reprocessed with validated Results Processor Tool" for previously submitted analytical studies also suggests reuse of data rather than new training.
9. How the Ground Truth for the Training Set Was Established
- Since the document doesn't explicitly detail a new "training set" for this specific submission, it also doesn't describe how ground truth for such a set was established. It's likely that the original assay development followed similar methods of using well-characterized samples or comparator assays for internal development and optimization.
- Regarding the Adaptive Crosstalk Correction (ACC) factor, the validation involved "testing of SARS-CoV-2 positive clinical specimens that are representative of those that yielded false positive Flu B results in the field." This indicates that the problem the ACC addresses arose from real-world performance, and the resolution was validated against specific clinical scenarios rather than a formal "training set" in the machine learning sense.
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(30 days)
And Other Microbial Agents
Additional Regulation Numbers: 21 CFR 866.2680, 21 CFR 866.3980, 21 CFR 862.2570
The BIOFIRE® SPOTFIRE® Respiratory/Sore Throat (R/ST) Panel Mini is a multiplexed polymerase chain reaction (PCR) test intended for use with the BIOFIRE® System for the simultaneous, qualitative detection and identification of multiple respiratory viral and bacterial nucleic acids in nasopharyngeal swab (NPS) specimens obtained from individuals with signs and symptoms of respiratory tract infection, including COVID-19; (Respiratory menu) or in throat swab (TS) specimens from individuals with signs and symptoms of pharyngitis (Sore Throat menu).
The following analytes are identified and differentiated using the SPOTFIRE R/ST Panel Mini:
Respiratory Menu:
Viruses
Coronavirus SARS-CoV-2
Human rhinovirus
Influenza A virus
Influenza B virus
Respiratory syncytial virus
Sore Throat Menu:
Viruses
Human rhinovirus
Influenza A virus
Influenza B virus
Respiratory syncytial virus
Bacteria
Streptococcus pyogenes (group A Strep)
Nucleic acids from the viral and bacterial organisms identified by this test are generally detectable in NPS/TS specimens during the acute phase of infection. The detection and identification of specific viral and bacterial nucleic acids from individuals exhibiting signs and symptoms of respiratory infection and/or pharyngitis is indicative of the presence of the identified microorganism and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.
Negative results in the setting of a respiratory illness and/or pharyngitis may be due to infection with pathogens that are not detected by this test, or a respiratory tract infection that may not be detected by an NPS or TS specimen. Positive results do not rule out co-infection with other organisms. The agent(s) detected by the SPOTFIRE R/ST Panel Mini may not be the definite cause of disease.
Additional laboratory testing (e.g., bacterial and viral culture, immunofluorescence, and radiography) may be necessary when evaluating a patient with possible respiratory tract infection and/or pharyngitis.
The SPOTFIRE R/ST Panel Mini simultaneously identifies 5 different respiratory viral pathogens in nasopharyngeal swabs (NPS) or 5 different viral and bacterial pharyngitis pathogens in throat swabs (TS) from individuals with signs and symptoms of respiratory tract infections or pharyngitis, respectively, (see Table 1) The SPOTFIRE R/ST Panel Mini is compatible with the BIOFIRE® System, a polymerase chain reaction (PCR)-based in vitro diagnostic system for infectious disease testing. The BIOFIRE System Sottware executes the SPOTFIRE R/ST Panel Mini test and interprets and reports the test results. The SPOTFIRE R/ST Panel Mini was designed to be used in CLIA-waived environments.
A test is initiated by loading Hydration Solution injection solution injection port of the SPOTFIRE R/ST Panel Mini pouch and NPS or TS specimen, mixed with the provided Sample injection port of the SPOTFIRE R/ST Panel Mini pouch and placing it in the SPOTFIRE System. The reagents required for specimen testing and analysis in a freeze-dried format; the addition of Hydration and Sample/Buffer Mix rehydrates the reagents. After the pouch is prepared, the SPOTFIRE System Software guides the user through the steps of placing the pouch into the instrument, scanning the sample identification, and initiating the run.
The SPOTFIRE System contains coordinated systems of inflatable bladders and seal points, which act on the pouch to control the movement of liquid between the pouch blisters. When a bladder is inflated over a reagent blister, it forces liquid from the blister into connecting channels. Alternatively, when a seal is placed over a connecting channel it acts as a valve to open or close a channel. In addition, electronically-controlled pneumatic pistons are positioned over multiple plungers in order to deliver the rehydrated reagents into the blisters at the appropriate times. Two Peltier devices control heating and cooling of the pouch to drive the PCR reactions and the melt curve analysis.
Nucleic acid extraction occurs within the SPOTFIRE R/ST Panel Mini pouch using mechanical Ivsis followed by purfication using standard magnetic bead technology. After extracting and purifying nucleic acids from the unprocessed sample, the SPOTFIRE System performs a nested multiplex PCR that is executed in two stage. During the first stage, the SPOTFIRE System performs a single, large volume, highly multiplexed reverse transcription PCR (rt-PCR) reaction. The products from first stage PCR are then diluted and combined with a fresh, primer-free master mix and a fluorescent doublestranded DNA binding dye (LC Green® Plus, BioFire Diagnostics). The solution is then distributed to each well of the array. Array wells contain sets of primers designed specifically to amplify sequences internal to the PCR products generated during the first stage PCR reaction. The 2nd stage PCR, or nested PCR, is performed in singleplex fashion in each well of the array. At the conclusion of the 2nd stage PCR, the array is interrogated by melt curve analysis for the detection of signature amplicons denoting the presence of specific targets. A digital camera placed in front of the 2nd stage PCR captures fluorescent images of the PCR reactions and software interprets the data.
The SPOTFIRE System Software automatically interprets the results of each DNA melt curve analysis and combines the data with the results of the internal pouch controls to provide a test result for each organism on the SPOTFIRE R/ST Panel Mini.
This document describes the BIOFIRE® SPOTFIRE® Respiratory/Sore Throat (R/ST) Panel Mini, a multiplex PCR test.
1. Table of Acceptance Criteria and Reported Device Performance
The document provides extensive analytical performance data rather than a direct comparison of acceptance criteria to reported clinical performance metrics (like PPA and NPA). However, the "Summary of Performance Data" for clinical studies does present sensitivity/PPA and specificity/NPA, which can be interpreted as the reported device performance against implied clinical acceptance criteria.
Clinical Performance Summary (NPS Specimens - Respiratory Menu)
Analyte | Performance Metric (Prospective) | % | 95% CI |
---|---|---|---|
Coronavirus SARS-CoV-2 (PPA) | 71/73 | 97.3 | 90.5-99.2% |
Coronavirus SARS-CoV-2 (NPA) | 1031/1037 | 99.4 | 98.7-99.7% |
Human rhinovirus (PPA) | 345/348 | 99.1 | 97.5-99.7% |
Human rhinovirus (NPA) | 695/767 | 90.6 | 88.3-92.5% |
Influenza A virus (PPA) | 0/0 (no positive cases identified) | - | - |
Influenza A virus (NPA) | 1115/1115 | 100 | 99.7-100% |
Influenza B virus (PPA) | 0/0 (no positive cases identified) | - | - |
Influenza B virus (NPA) | 1110/1110 | 100 | 99.7-100% |
Respiratory syncytial virus (PPA) | 26/27 | 96.3 | 81.7-99.3% |
Respiratory syncytial virus (NPA) | 1086/1088 | 99.8 | 99.3-100% |
Clinical Performance Summary (TS Specimens - Sore Throat Menu)
Analyte | Performance Metric (Prospective) | % | 95% CI |
---|---|---|---|
Human rhinovirus (Sensitivity/PPA) | 202/213 | 94.8 | 91.0-97.1% |
Human rhinovirus (Specificity/NPA) | 619/662 | 93.5 | 91.4-95.1% |
Influenza A virus (Sensitivity/PPA) | 35/35 | 100 | 90.1-100% |
Influenza A virus (Specificity/NPA) | 840/840 | 100 | 99.5-100% |
Influenza B virus (Sensitivity/PPA) | 4/4 | 100 | 51.0-100% |
Influenza B virus (Specificity/NPA) | 872/872 | 100 | 99.6-100% |
Respiratory syncytial virus (Sensitivity/PPA) | 21/24 | 87.5 | 69.0-95.7% |
Respiratory syncytial virus (Specificity/NPA) | 849/851 | 99.8 | 99.1-99.9% |
Streptococcus pyogenes (PPA - PCR) | 209/217 | 96.3 | 92.9-98.1% |
Streptococcus pyogenes (NPA - PCR) | 654/660 | 99.1 | 98.0-99.6% |
Streptococcus pyogenes (Sensitivity - Culture) | 174/177 | 98.3 | 95.1-99.4% |
Streptococcus pyogenes (Specificity - Culture) | 654/692 | 94.5 | 92.6-96.0% |
Analytical Acceptance Criteria and Results for key studies:
Study | Acceptance Criteria | Reported Device Performance (Results) |
---|---|---|
Sample Storage and Handling | 100% expected positive results in all samples tested for each organism. Crossing point (Cp) values evaluated and trended across conditions to assess analyte stability. | Positive results were observed in 100% of all TSa samples tested at all conditions evaluated for all SPOTFIRE R/ST Panel Mini analytes. |
Limit of Detection (LoD) | LoD confirmed when positive results were reported in at least 95% (≥19/20) of replicates tested at 1x LoD, and fewer than 95% (≤18/20) of replicates tested at 0.1x LoD. Equivalent detection in single and multi-analyte samples based on concordance of positive/negative results. | The LoD concentrations for the SPOTFIRE R/ST Panel Mini analytes were confirmed in viable or infectious units and/or nucleic acid copies/mL. The panel accurately detected viruses and bacteria in samples contrived in either VTM or Amies media containing one or multiple organisms. |
Analytical Reactivity (Inclusivity) | Assay reactivity of each isolate confirmed if positive results were reported for the appropriate analyte in 3/3 or 4/5 replicates tested within 10x LoD. If fewer than 4/5 replicates, additional testing at 100x LoD or higher. Isolates with reactivity limitations noted in product literature. | Analytical reactivity testing demonstrated that the SPOTFIRE R/ST Panel Mini can detect and accurately report results for a diverse collection of isolates from a variety of strains, serotypes, and genotypes with few limitations. (Limitations noted in conclusion include rare S. pyogenes strains not detected). |
Analytical Specificity (Exclusivity) | On-panel organisms expected positive for target analyte and negative for others. Off-panel organisms expected negative for all panel analytes, unless otherwise indicated. | Three cross-reactivities were identified by empirical and/or in silico evaluations: SARS-CoV-2 with closely related sarbecoviruses, some Bordetella species with Human Rhinovirus (at high concentration), and some bovine/canine picornaviruses with Human Rhinovirus. These limitations are noted in the device labeling. |
Interference | Primary results evaluated: pass/fail/invalid for internal controls, and analyte positive/negative results. If unexpected result/control failure for one replicate, retested in two additional pouches. | Accurate results for the SPOTFIRE R/ST Panel Mini were reported in the presence of a variety of potentially interfering substances (endogenous, exogenous, technique-specific, microorganisms). |
Near-LoD/Reproducibility | Minimum of 90% agreement with expected positive results (≥95% desired) for all organisms. Minimum of 95% agreement with expected negative results. | For positive samples, agreement with expected positive results (all systems/sites) was ≥98% for all analytes. Agreement with expected negative results was 100% for all analytes. Total positive agreement nearly identical between BioFire and clinical sites (99.8% vs. 99.0%). |
Matrix Validation | Equivalent performance between artificial and natural matrices based on agreement of positive and negative results at each test concentration. Considered equivalent if negative results observed at same or similar test concentration. | Equivalent results achieved when samples prepared in natural and artificial NPS or natural and artificial TS matrices and tested with the SPOTFIRE R/ST Panel Mini. |
Transport Media Validation | Primary metric: percent agreement between candidate medium and control medium (CDC VTM) for each spiked analyte at each test concentration. 100% agreement when testing above LoD and ≥95% at LoD for compatibility. | Equivalent analyte detection observed for all representative analytes when samples were prepared in each of the candidate media types (BD™ Universal Viral Transport, and Remel MicroTest™ M4RT® Multi-Microbe Media) compared to the control medium (CDC VTM). |
Sample Carry Over | Positive and negative analyte results evaluated. Positive samples expected positive for target and negative for others. Negative samples expected negative for all analytes. | No unexpected positive results were observed in this study. |
2. Sample Sizes and Data Provenance
- Clinical Performance (Test Set):
- NPS Specimens (Respiratory Menu - Prospective): Total of 1115 specimens. The document doesn't explicitly state the country of origin but implies clinical sites (e.g., "as tested by intended users"). This is prospective data.
- NPS Specimens (Respiratory Menu - Archived): Used for some analytes, e.g., Human Rhinovirus (30 positive, 454 negative), Influenza A (59 positive, 423 negative), Influenza B (30 positive, 28 negative), RSV (37 positive, 447 negative). This is retrospective data.
- TS Specimens (Sore Throat Menu - Prospective): Total of 876 specimens for most viral targets. Streptococcus pyogenes had 217 positive (PCR) / 177 positive (Culture) and 660 negative (PCR) / 692 negative (Culture). This is prospective data.
- TS Specimens (Sore Throat Menu - Archived): Used for some analytes, e.g., Human Rhinovirus (2 positive, 57 negative), Influenza A (11 positive, 44 negative), Influenza B (20 positive, 0 negative), RSV (2 positive, 57 negative), Streptococcus pyogenes (39 positive, 10 negative). This is retrospective data.
- TS Specimens (Sore Throat Menu - Contrived): Used for some analytes, e.g., Influenza A (93 positive, 332 negative), Influenza B (49 positive, 333 negative), RSV (50 positive, 381 negative). This would be laboratory-generated data.
3. Number of Experts and Qualifications for Ground Truth
The document does not specify the number or qualifications of experts used to establish the ground truth for the clinical test set. It mentions using "molecular assays or known specimen composition" as comparator methods for most analytes, and "culture" as the reference method for Streptococcus pyogenes.
4. Adjudication Method
The document does not describe any specific adjudication method (e.g., 2+1, 3+1) for establishing the ground truth or resolving discrepancies in the clinical test set.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study is mentioned or implied, as this device is an in vitro diagnostic (IVD) PCR test for direct pathogen detection, not an AI-assisted diagnostic imaging or interpretation tool for human readers. Therefore, the concept of "human readers improve with AI vs without AI assistance" does not apply.
6. Standalone Performance
Yes, the studies described are for standalone performance. The BIOFIRE® SPOTFIRE® R/ST Panel Mini provides automated interpretation and reporting of test results based on the PCR assay. It is designed to be used independently to generate a qualitative detection and identification of microbial nucleic acids.
7. Type of Ground Truth Used
- Clinical Performance (Prospective/Archived): The ground truth for most analytes was established using molecular assays or, in some cases, known specimen composition. For Streptococcus pyogenes, culture was also used as a reference method for some comparisons.
- Analytical Performance (LoD, Inclusivity, Exclusivity, Interference, Reproducibility, Matrix Validation, Transport Media Validation, Carry Over): The ground truth was established through known specimen composition (e.g., contrived samples with known concentrations of organisms, presence of interfering substances, specific transport media).
8. Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of machine learning or AI algorithm development. This device is a PCR-based test, and its performance is validated through analytical and clinical studies, not typically through a machine learning training phase with a distinct dataset. The "training" in this context refers to the development and optimization of the PCR primers, probes, and reaction conditions.
9. How the Ground Truth for the Training Set Was Established
Given that this is a PCR diagnostic device, not an AI algorithm in the typical sense of needing a "training set" for model learning, this question isn't directly applicable. The "ground truth" for developing and optimizing the PCR assays themselves would have been established through:
- Careful selection and validation of synthetic nucleic acid targets.
- Testing with characterized microbial isolates and clinical samples whose status was confirmed by established reference methods (e.g., sequencing, culture, validated molecular tests).
- In silico analysis of genetic sequences to design primers and probes with high specificity and inclusivity.
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And Other Microbial Agents
Additional Requlation Numbers: 21 CFR 866.2680. 21 CFR 866.3980. 21 CFR 862.2570
The BIOFIRE® SPOTFIRE® Respiratory/Sore Throat (R/ST) Panel is a multiplexed polymerase chain reaction (PCR) test intended for use with the BIOFIRE® System for the simultaneous, qualitative detection and identification of multiple respiratory viral and bacterial nucleic acids in nasopharyngeal swab (NPS) specimens obtained from individuals with signs and symptoms of respiratory tract infection, including COVID-19; (Respiratory menu) or in throat swab (TS) specimens from individuals with signs and symptoms of pharyngitis (Sore Throat menu).
The following organism types and subtypes are identified and differentiated using the SPOTFIRE R/ST Panel:
Respiratory Menu Viruses Adenovirus Coronavirus SARS-CoV-2 Coronavirus (seasonal) Human metapneumovirus Human rhinovirus/enterovirus Influenza A virus Influenza A virus/H1-2009 Influenza A virus/ H3 Influenza B virus Parainfluenza virus Respiratory syncytial virus
- Bacteria Bordetella parapertussis Bordetella pertussis Chlamydia pneumoniae Mycoplasma pneumoniae
Sore Throat Menu Viruses Adenovirus Coronavirus (seasonal) Human metapneumovirus Human rhinovirus/enterovirus Influenza A virus Influenza A virus/H1-2009 Influenza A virus/H3 Influenza B virus Parainfluenza virus Respiratory syncytial virus
Bacteria Chlamydia pneumoniae Mycoplasma pneumoniae Streptococcus dysgalactiae (Group C/G Strep) Streptococcus pyogenes (Group A Strep)
Nucleic acids from the viral and bacterial organisms identified by this test are generally detectable in NPS/TS specimens during the acute phase of infection and identification of specific viral and bacterial nucleic acids from individuals exhibiting signs and symptoms of respiratory infection and/or pharyngtis are indicative of the identified microorganism and aids in diagnosis if used in conjunction with other clinical and epidemiological information, and laboratory findings. The results of this test should not be used as the sole basis for diagnosis, treatment, or other patient management decisions.
Negative results in the setting of a respiratory illness and/or pharyngitis may be due to infection with pathogens that are not detected by this test, or a respiratory tract infection that may not be detected by an NPS or TS specimen. Positive results do not rule out coinfection with other organisms. The agent(s) detected by the SPOTFIRE R/ST Panel may not be the definite cause of disease.
Additional laboratory testing (e.g., bacterial and viral culture, immunofluorescence, and radiography) may be necessary when evaluating a patient with possible respiratory tract infection and/or pharyngitis.
The SPOTFIRE R/ST Panel simultaneously identifies 15 different respiratory viral and bacterial pathogens in nasopharyngeal swabs (NPS) or 14 viral and bacterial pharyngitis pathogens in throat swabs (TS) from individuals with signs and symptoms of respiratory tract infections or pharyngitis, respectively, (see Intended Use:). The SPOTFIRE R/ST Panel is compatible with the SPOTFIRE System, a polymerase chain reaction (PCR)-based in vitro diagnostic system for infectious disease testing. The SPOTFIRE System Software executes the SPOTFIRE R/ST Panel test and interprets and reports the test results. The SPOTFIRE RIST Panel was designed to be used in CLIA-waived environments. A test is initiated by loading Hydration Solution into one port of the SPOTFIRE R/ST Panel pouch and NPS or TS specimen, mixed with the provided Sample Buffer, into the port of the SPOTFIRE R/ST Panel pouch and placing it in the SPOTFIRE System. The pouch contains all of the reagents required for specimen testing and analysis in a freeze-dried format; the addition of Hydration Solution and Sample/Buffer Mix rehydrates the reagents. After the pouch is prepared, the SPOTFIRE System Software guides the user through the steps of placing the instrument, scanning the pouch barcode, entering the sample identification, and initiating the run.
The SPOTFIRE System contains coordinated systems of inflatable bladders and seal points, which act on the pouch to control the movement of liguid between the pouch blisters. When a bladder is inflated over a reagent blister, it forces liguid from the blister into connecting channels. Alternatively, when a seal is placed over a connecting channel it acts as a valve to open or close a channel. In addition, electronically controlled pneumatic pistons are positioned over multiple plungers in order to deliver the rehydrated reagents into the blisters at the appropriate times. Two Peltier and cooling of the pouch to drive the PCR reactions and the melt curve analysis.
Nucleic acid extraction occurs within the SPOTFIRE R/ST Panel pouch using mechanical and chemical lysis followed by purification using standard magnetic bead technology. After extracting and purifying nucleic acids from the unprocessed sample, the SPOTFIRE System performs a nested multiplex PCR that is executed in two stage, the SPOTFIRE System performs a single, large volume, highly multiplexed reverse transcription PCR (rt-PCR) reaction. The products from first stage PCR are then diluted and combined with a fresh, primer-free master mix and a fluorescent doublestranded DNA binding dye (LC Green® Plus, BioFire Diagnostics). The solution is then distributed to each well of the array. Array wells contain sets of primers designed specifically to amplify sequences internal to the PCR products generated during the first stage PCR reaction. The 2nd stage PCR, is performed in singleplex fashion in each well of the array. At the conclusion of the 2nd stage PCR, the array is interrogated by melt curve analysis for the detection of signature amplicons denoting the presence of specific targets. A digital camera placed in front of the 2nd stage PCR captures fluorescent images of the PCR reactions and software interprets the data.
The SPOTFIRE System Software automatically interprets the results of each DNA met curve analysis and combines the data with the results of the internal pouch controls to provide a test result for each organism on the SPOTFIRE R/ST Panel.
Here's a breakdown of the acceptance criteria and study proving the device meets those criteria, based on the provided FDA 510(k) summary for the BIOFIRE® SPOTFIRE® Respiratory/Sore Throat (R/ST) Panel:
The document describes the BIOFIRE® SPOTFIRE® Respiratory/Sore Throat (R/ST) Panel, a multiplexed PCR test for simultaneous, qualitative detection and identification of multiple respiratory viral and bacterial nucleic acids. The data presented primarily focuses on analytical performance and clinical performance to demonstrate substantial equivalence to a predicate device.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are generally implied by the performance metrics reported, specifically the Positive Percent Agreement (PPA) / Sensitivity and Negative Percent Agreement (NPA) / Specificity. For analytical studies, acceptance criteria related to percentages of positive results and agreement levels are explicitly stated.
Clinical Performance Acceptance Criteria (Implied by Data Reported):
For each analyte, the acceptance criteria are generally to achieve high PPA and NPA. While specific numerical thresholds for PPA/NPA are not explicitly listed as "acceptance criteria" in the clinical tables themselves, the FDA's clearance implies that the presented performance met their internal requirements for substantial equivalence. For diagnostic tests, generally, PPA and NPA values in the high 90s are expected.
Analytical Performance Acceptance Criteria and Reported Performance:
Study | Acceptance Criteria | Reported Device Performance and Conclusion |
---|---|---|
Clinical Performance (NPS Specimens) | High Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) for each analyte. (Specific numerical thresholds not explicitly stated as acceptance criteria in the table but are implied by the nature of regulatory submissions for diagnostic tests.) | Table 2. R/ST Panel Performance Summary for NPS Specimens (Respiratory Menu): |
Across prospective and archived studies, PPAs for individual viruses ranged from 96.3% (Respiratory syncytial virus) to 100% (Adenovirus, Human metapneumovirus, Influenza A A/H3, Influenza B, Chlamydia pneumoniae, Mycoplasma pneumoniae). NPAs for individual viruses ranged from 90.6% (Human rhinovirus/enterovirus) to 100% (Human metapneumovirus, Influenza A, Influenza A A/H1-2009, Influenza A A/H3, Influenza B, Bordetella parapertussis, Bordetella pertussis, Chlamydia pneumoniae, Mycoplasma pneumoniae). Overall high performance observed. | ||
Clinical Performance (TS Specimens) | High Sensitivity / PPA and Specificity / NPA for each analyte. (Specific numerical thresholds not explicitly stated as acceptance criteria in the table but are implied by the nature of regulatory submissions for diagnostic tests.) | Table 3. R/ST Panel Performance Summary for TS Specimens (Sore Throat Menu): |
Across prospective, archived, and contrived studies, Sensitivities/PPAs for individual viruses ranged from 81.8% (Adenovirus, archived) to 100% (multiple analytes). Specificities/NPAs for individual viruses ranged from 91.7% (Adenovirus, archived) to 100% (multiple analytes). Overall high performance observed, with some variations based on study type (e.g., contrived samples often showing 100% agreement due to controlled conditions). Culture was used as the reference method for Streptococcus dysgalactiae and Streptococcus pyogenes. | ||
Sample Storage and Handling | "For the storage condition to be considered acceptable for each organism, 100% expected positive results were required to be observed in all samples tested. In addition, crossing point (Cp) values were evaluated for each relevant assay and trended across the conditions to assess analyte stability over time." | "Positive results were observed in 100% of all TSa samples tested at all conditions evaluated for all SPOTFIRE R/ST Panel analytes." |
Conclusion: "The SPOTFIRE R/ST Panel provides accurate results when TS specimens are stored in Amies media for up to 4 hours at ambient temperature (15-25 °C), up to 3 days at refrigerated temperature (2-8 °C), and up to 30 days at frozen temperature (≤ -15 °C). Similar results were previously observed with NPS specimens stored in transport media." | ||
Limit of Detection (LoD) | "The LoD for each SPOTFIRE R/ST Panel analyte was confirmed when positive results were reported in at least 95% (≥19/20) of replicates tested at the LoD (1× LoD), and fewer than 95% (≤18/20) of replicates tested at a concentration 10-fold below LoD (0.1× LoD). Equivalent detection of representative analytes in single analyte and multi-analyte samples was determined primarily based on concordance of positive or negative results at each test concentration." | "The LoD concentrations for the SPOTFIRE R/ST Panel analytes were confirmed...The panel accurately detected viruses and bacteria in samples contrived in either VTM or Amies media containing one or multiple organisms." |
Conclusion: "The SPOTFIRE R/ST panel provides accurate detection results for all analytes in single or polymicrobial specimens when present at or above the LoD. No adverse effect on the analytical sensitivity of the SPOTFIRE R/ST Panel was observed when evaluating multi-analyte specimens." | ||
Analytical Reactivity (Inclusivity) | "The assay reactivity of each isolate was confirmed if positive results were reported for the appropriate analyte in 3/3 or 4/5 replicates tested within 10× LoD. If positive results were reported in fewer than 4/5 replicates, additional testing was performed at 100× LoD or higher." | "Analytical reactivity testing demonstrated that the SPOTFIRE R/ST Panel can detect and accurately report results for a diverse collection of isolates from a variety of strains, serotypes, and genotypes of species collected over many years and from geographically distinct locations with few limitations." Specific limitations related to Streptococcus dysgalactiae and Streptococcus pyogenes were identified and noted in device labeling. |
Analytical Specificity (Exclusivity) | "On-panel organisms were expected to have a positive result for the analyte being tested and negative results for all other analytes targeted by the panel. Off-panel organisms were expected to have negative results for all panel analytes, unless otherwise indicated." | "Six cross-reactivities were identified by empirical and/or in silico evaluations that are predicted to cause inaccurate test results...Five of the identified cross-reactivities are either due to reactivity between phylogenetic near-neighbors that are rarely observed in human populations or were further evaluated and found to not impact the panel's specificity relevant to the intended use." Specific limitations related to SARS-CoV-2, B. bronchiseptica, Bordetella species, influenza A viruses of swine origin, bovine/canine picornaviruses, and Chlamydia gallinacea were identified and noted in device labeling. |
Interference (Interfering Substances) | "If an unexpected result or control failure was observed for one replicate of a sample containing a potentially interfering substance, the affected sample was retested in two additional pouches to determine if the failure was reproducible." Implied: accurate results should be maintained in the presence of interfering substances. | "Accurate results for the SPOTFIRE R/ST Panel were reported in the presence of a variety of potentially interfering substances...". |
Conclusion: "The SPOTFIRE R/ST Panel provides accurate results in the presence of various potentially interfering substances." A warning about bleach was noted. | ||
Near-LoD/Reproducibility | "For all organisms, a minimum of 90% agreement with the expected positive results (with 95% agreement desired) to demonstrate the reproducibility of positive results, and a minimum of 95% agreement with the expected negative results was required." | "For positive samples, agreement with the expected positive results (all systems/sites) was $\ge$ 95% for all analytes. The agreement with the expected negative results was 100% for all analytes. The total positive agreement reported for testing completed at BioFire and at clinical sites was nearly identical (99.1% (2052/2070) and 98.9% (1365/1380), respectively)..." |
Conclusion: "The SPOTFIRE R/ST Panel provides accurate and reproducible analyte detection results over time and in actual use conditions when testing was performed over multiple days, by operators with differing skill levels, at different sites, using different SpotFire Systems and different reagent kit lots. ... support use of the SPOTFIRE R/ST Panel and SPOTFIRE System at sites that hold a CLIA Certificate of Waiver." | ||
Matrix Validation | "Equivalent performance between the artificial and natural sample matrices was determined primarily based on agreement of positive and negative results at each test concentration. Artificial and natural matrices were considered equivalent if negative results were observed at the same or similar test concentration." | "Performance of the SPOTFIRE R/ST Panel was determined to be equivalent in natural and artificial NPS (nNS and aNS) and in natural and artificial throat swab (nTS and aTS) matrices for five representative panel analytes. In all cases, negative results were observed in artificial and natural matrices at the same or similar test concentrations." |
Conclusion: "The results of this study demonstrated that the artificial NPS and artificial TS matrices were acceptable for use in analytical evaluation of SPOTFIRE R/ST Panel performance." | ||
Transport Media Validation | "If the overall agreement was 100% when testing above the LoD and ≥95% when testing at the LoD, then the candidate medium was determined to be compatible. It was acceptable for the agreement to be less than 95% when testing below the LoD." | "Equivalent analyte detection was observed for all representative analytes when samples were prepared in each of the candidate media types (BD™ Universal Viral Transport, and Remel MicroTest™ M4RT® Multi-Microbe Media) compared to the control medium (CDC VTM)." |
Conclusion: "The SPOTFIRE R/ST Panel demonstrated equivalent results when samples were prepared in Viral Transport Media, BD™ Universal Viral Transport, and Remel MicroTest™ M4RT® Multi-Microbe Media. These transport media are indicated in the product labeling as suitable for use with the SPOTFIRE R/ST Panel." | ||
Sample Carry Over | "For positive samples, a positive result was expected for the analyte being tested and negative results were expected for all other analytes on the panel. Negative samples were expected to have a negative result for all analytes." Implied: No unexpected positive results due to carry-over. | "No unexpected positive results were observed in this study." |
Conclusion: "This study demonstrated that sample-to-sample carry-over between samples containing high concentrations of organism and negative samples is unlikely to occur and that carry-over poses an acceptable risk to the accuracy of the SPOTFIRE R/ST Panel test results when testing is performed according to the instructions for use." |
2. Sample Sizes Used for the Test Set and Data Provenance
The sample sizes vary by analyte and study type (prospective, archived, contrived).
-
Clinical Performance (Test Set):
- NPS Specimens (Respiratory Menu):
- Prospective Data: The total number of NPS specimens tested across all viruses and bacteria is not explicitly stated as a single number but can be aggregated from the "Positive" and "Negative" counts for each analyte. For example, for Adenovirus, there were 33 positives and 1082 negatives, totaling 1115 prospective NPS specimens where Adenovirus was assessed. This appears to be the total number of clinical samples evaluated in the prospective study.
- Archived Data: Similarly, for Adenovirus, there were 31 positives and 439 negatives, totaling 470 archived NPS specimens.
- Contrived Data: Indicated as 0/0 for all NPS analytes, suggesting contrived samples were not used for clinical performance evaluation of NPS specimens.
- TS Specimens (Sore Throat Menu):
- Prospective Data: For Adenovirus, 65 positives and 810 negatives (total 875). This seems to be the total number of clinical throat swab specimens assessed.
- Archived Data: For Adenovirus, 11 positives and 48 negatives (total 59).
- Contrived Data: For Adenovirus, 50 positives and 381 negatives (total 431). Contrived samples were used for TS clinical performance studies.
- Data Provenance: The document states "as tested by intended users," implying clinical sites. No specific country of origin is mentioned, but typically, these studies for FDA clearance involve sites within the US. The "Prospective" studies indicate prospective collection, while "Archived" refers to retrospective samples. "Contrived" samples are laboratory-prepared.
- NPS Specimens (Respiratory Menu):
-
Analytical Performance (Test Set):
- Limit of Detection (LoD): At least 20 replicates (e.g., 19/20) tested at LoD and 10-fold below LoD for each analyte.
- Analytical Reactivity (Inclusivity): 3/3 or 4/5 replicates tested within 10x LoD for each isolate.
- Near-LoD/Reproducibility: Not explicitly stated but mentions "multiple days," "multiple operators," "three unique SPOTFIRE Systems," "three distinct clinical sites holding a CLIA waiver." The reported positive and negative agreement totals are 2070 (BioFire) and 1380 (clinical sites) tests.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and the Qualifications of Those Experts
The document does not specify the number of experts or their qualifications (e.g., radiologist with 10 years of experience
) used to establish the ground truth. This is a common characteristic of in vitro diagnostic (IVD) submissions focusing on molecular diagnostic tests.
- For molecular tests, the "ground truth" is typically established by comparator methods, often laboratory-developed tests (LDTs) or other cleared/validated molecular diagnostic assays (e.g., PCR followed by sequencing, or highly sensitive and specific reference PCR methods).
- For bacterial culture (used for Streptococcus dysgalactiae and Streptococcus pyogenes), the ground truth is established by standard microbiological culture and identification techniques, performed by trained laboratory personnel.
4. Adjudication Method for the Test Set
The document does not describe a formal adjudication method (e.g., 2+1, 3+1) for the clinical test sets. This is expected given that the ground truth is established by laboratory reference methods (molecular or culture), which typically do not involve human reader adjudication in the same way imaging studies might. Any discrepancies between the investigational device and the reference method would be investigated by the manufacturer, rather than through an expert consensus adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, an MRMC comparative effectiveness study was not done. This type of study is primarily relevant for imaging-based AI devices where human readers interpret medical images, and the AI assists or augments their performance. The BIOFIRE SPOTFIRE R/ST Panel is a molecular diagnostic test where the output is an automated detection of nucleic acids, not an interpretation by a human reader that could be augmented by AI.
6. If a Standalone (i.e. Algorithm Only Without Human-in-the Loop Performance) Was Done
Yes, the performance data presented (Tables 2 and 3 for Clinical Performance, and Table 4 for Analytical Performance) represents the standalone performance of the BIOFIRE SPOTFIRE R/ST Panel, which includes the instrument and its automated software interpretation. The device itself is designed to provide automated results without human interpretive input for the detection of targets. The "as tested by intended users" for clinical performance indicates that the device was used in a realistic setting, but the performance metrics reflect the direct output of the system.
7. The Type of Ground Truth Used
The ground truth for the clinical performance evaluation was established using:
- Comparator molecular assays or known specimen composition for most analytes (referred to as "molecular assays or known specimen composition were used as comparator methods" for PPA/NPA). This suggests a combination of validated PCR assays, and potentially sequencing for confirmation.
- Culture for Streptococcus dysgalactiae (Group C/G Strep) and Streptococcus pyogenes (Group A Strep). This is explicitly stated: "Performance measures of sensitivity and specificity refer to the prospective and archived Streptococcus and archived Streptococcus analytes for which culture was used as the reference method."
For analytical studies, the ground truth was established by:
- Known concentrations of organisms (e.g., viable or infectious units, nucleic acid copies/mL) for LoD and Inclusivity studies.
- Defined panels of organisms or substances for Exclusivity and Interference studies.
8. The Sample Size for the Training Set
This document does not provide information on the training set size directly. The presented studies are for validation/testing of the device's performance. For molecular diagnostic assays like this, the 'training' of the algorithms (e.g., primer design, melt curve analysis interpretation) typically happens during the assay development phase, often using synthetic targets, cultured organisms, and preliminary clinical samples. However, this is not detailed in a 510(k) summary, which focuses on validation data against a defined product. The "software was verified and validated" statement implies that developmental data was used, but details on sample size for that specific phase are not provided in this regulatory summary.
9. How the Ground Truth for the Training Set Was Established
Since the training set details are not provided, the method for establishing its ground truth is also not explicitly stated in this document. However, based on typical IVD development practices:
- Ground truth for assay development (which informs the 'training' of a molecular diagnostic system) would involve well-characterized positive and negative controls, reference strains, and potentially sequenced clinical isolates.
- Molecular target sequences (
in silico
analysis) - Analytical dilution series where the exact concentration of the pathogen is known.
- Samples confirmed by multiple, orthogonal laboratory methods.
The rigorous analytical and clinical studies described in the results section serve as the validation of the final trained/developed system.
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(160 days)
21 CFR 866.3860, Trichomonas vaginalis Nucleic
Acid Amplification Test System, OUY
21 CFR 862.2570
The Xpert® Xpress MVP test, performed on the GeneXpert® Xpress System, is an automated qualitative in vitro diagnostic test for the detection of DNA targets from anaerobic bacteria associated with bacterial vaginosis (BV), Candida species associated with vulvovaginal candidiasis, and Trichomonas vaginalis. The Xpert Xpress MVP test uses clinician-collected and self-collected vaginal swabs (collected in a clinical setting) from patients who are symptomatic for vaginitis/vaginosis. The Xpert Xpress MVP test utilizes real-time polymerase chain reaction (PCR) for the amplification of specific DNA targets and utilizes fluorogenic target-specific hybridization probes to detect and differentiate DNA from:
- Organisms associated with bacterial vaginosis (detected organisms not reported individually) .
- Atopobium spp. (Atopobium vaginae, Atopobium novel species CCUG 55226) O
- Bacterial Vaginosis-Associated Bacterium 2 (BVAB2) O
- Megasphaera-1 O
- Candida spp. (C. albicans, C. tropicalis, C. parapsilosis, C. dubliniensis, species not differentiated) .
- Candida glabrata/Candida krusei (species not differentiated) ●
- . Trichomonas vaginalis
The Xpert Xpress MVP test is intended to aid in the diagnosis of vaginal infections in women with a clinical presentation consistent with bacterial vaginosis, vulvovaginal candidiasis, or trichomoniasis.
The Xpert® Xpress MVP test is an automated in vitro diagnostic test for qualitative detection of DNA targets from anaerobic bacteria associated with bacterial vaginosis (BV), Candida species associated with vulvovaginal candidiasis, and Trichomonas vaginalis, the agent of trichomoniasis. In the CLIA-waived environment, the Xpert Xpress MVP test is performed on the GeneXpert® Xpress System.
The latest Hub configuration of the GeneXpert Xpress System consists of a GeneXpert IV instrument that executes sample preparation, nucleic acid amplification and real-time fluorescent signal detection for the tests, and a GeneXpert Hub with preloaded GeneXpert Xpress software for running the tests and viewing the test results. The GeneXpert Hub accessory integrates the computer, touchscreen monitor and barcode scanner. Each of the GeneXpert modules in the GeneXpert IV instrument can perform independent sample preparation and testing.
The Xpert Xpress MVP test is a PCR-based Nucleic Acid Amplification Test. Each test requires the use of a single-use disposable GeneXpert cartridge that contains all necessary reagents for the detection of DNA from BV organisms, Candida species, and Trichomonas vaginalis. A Sample Processing Control (SPC) and a Probe Check Control (PCC) are also included in the cartridge serving as internal controls. The SPC is present to control for adequate sample processing, to monitor PCR conditions, the presence of potential inhibitor(s) and possible reagent degradation. The PCC verifies reagent rehydration. PCR tube filling, and confirms that all reaction components are present in the cartridge including monitoring for probe integrity and dye stability. Because the cartridges are self-contained, the risk of cross- contamination between samples is minimized.
The Xpert Xpress MVP test is designed for use with the following specimens collected from symptomatic individuals: self-collected vaginal swabs (collected in a clinical setting) and clinician-collected vaginal swabs. The ancillary specimen collection kit for use with the Xpert Xpress MVP test is the Xpert Swab Specimen Collection Kit. The swab and the transport reagent included in the Xpert Swab Specimen Collection Kit are designed to collect and preserve patient specimens to allow transport to the testing site prior to analysis with the Xpert Xpress MVP test.
Here's a summary of the acceptance criteria and study details for the Cepheid Xpert Xpress MVP device based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance:
The document doesn't explicitly state "acceptance criteria" in a numerical, threshold-based format. Instead, it presents the clinical performance results (PPA/NPA, Sensitivity/Specificity) for the Xpert Xpress MVP test. The implication is that these reported performance metrics meet internal or regulatory acceptance thresholds for substantial equivalence.
Target | Metric (Clinical Study) | Clinician-collected (CVS) Performance (95% CI) | Self-collected (SVS) Performance (95% CI) |
---|---|---|---|
BV | PPA | 92.9% (429/462) (90.1% - 94.9%) | 93.5% (434/464) (90.9% - 95.4%) |
NPA | 94.5% (719/761) (92.6% - 95.9%) | 93.6% (711/760) (91.6% - 95.1%) | |
Candida group* | Sensitivity | 98.1% (360/367) (96.1% - 99.1%) | 97.8% (359/367) (95.8% - 98.9%) |
Specificity | 94.9% (820/864) (93.2% - 96.2%) | 92.9% (804/865) (91.0% - 94.5%) | |
Candida glab-krus | Sensitivity (Fresh Pros.) | 94.1% (32/34) (80.9% - 98.4%) | 100% (33/33) (89.6% - 100%) |
Specificity (Fresh Pros.) | 99.8% (1195/1197) (99.4% - 99.9%) | 99.7% (1195/1199) (99.1% - 99.9%) | |
Sensitivity (Contrived) | 99.0% (98/99) (94.5%-99.8%) | N/A | |
Specificity (Contrived) | 96.4% (27/28) (82.3%-99.4%) | N/A | |
TV | PPA (Fresh Pros.) | 98.0% (48/49) (89.3% - 99.6%) | 97.9% (47/48) (89.1% - 99.6%) |
NPA (Fresh Pros.) | 99.6% (1155/1160) (99.0% - 99.8%) | 99.7% (1159/1162) (99.2% - 99.9%) | |
PPA (Contrived) | 94.4% (84/89) (87.5%-97.6%) | N/A | |
NPA (Contrived) | 100% (29/29) (88.3%-100%) | N/A |
*Target includes C. albicans, C. tropicalis, C. parapsilosis, and C. dubliniensis
2. Sample Size for the Test Set and Data Provenance:
- Sample Size:
- Clinical Study: 1,275 female patients (18 to ≥50 years of age, plus two patients 14-17 years old). A total of 2,544 vaginal swabs were tested (likely one clinician-collected and one self-collected per patient).
- Data Provenance: Retrospective and prospective. The clinical study was conducted at 9 geographically diverse sites in the U.S.
3. Number of Experts Used to Establish Ground Truth and Qualifications:
The document does not specify the number or qualifications of experts used to establish the ground truth for the clinical study. It refers to "reference/comparator methods" for ground truth.
4. Adjudication Method for the Test Set:
- For BV, Candida group, Candida glab-krus, and TV, the performance was determined relative to specific reference/comparator methods (see point 7).
- For discrepant results, "investigation of discrepant results was performed by testing specimens with another FDA-cleared NAAT." This indicates a form of discrepancy resolution rather than a multi-expert adjudication on all cases. The exact adjudication method (e.g., 2+1, 3+1) for discrepant cases is not detailed, but it involves re-testing with an FDA-cleared NAAT.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:
No MRMC comparative effectiveness study was mentioned. The device is an in vitro diagnostic test, which typically does not involve human readers interpreting images or data to the same extent as AI-assisted diagnostic tools. Performance is typically compared against reference methods.
6. Standalone (Algorithm Only) Performance:
Yes, the entire clinical study and analytical studies described are standalone performance evaluations of the Xpert Xpress MVP device (an automated qualitative in vitro diagnostic test) without human-in-the-loop assistance in its diagnostic output. Its output is a qualitative detection result (Positive/Negative/Not Detected).
7. Type of Ground Truth Used:
- Bacterial Vaginosis (BV): An FDA-cleared nucleic acid amplification test (NAAT).
- Candida group (C. albicans, C. tropicalis, C. parapsilosis, C. dubliniensis): Yeast culture followed by mass spectrometry for species identification.
- Candida glabrata/Candida krusei: Yeast culture followed by mass spectrometry for species identification.
- Trichomonas vaginalis (TV): A patient infected status (PIS) algorithm that included results from an FDA-cleared NAAT and TV culture.
- Discrepant Results: Re-tested with another FDA-cleared NAAT.
8. Sample Size for the Training Set:
The document does not explicitly mention a "training set" in the context of machine learning model development. This device is a PCR-based NAAT, not an AI/ML-driven diagnostic. Therefore, the concept of a training set for an algorithm is not directly applicable in the same way as for an image-based AI device. Analytical studies (e.g., Limit of Detection, Analytical Reactivity, Analytical Specificity) and reproducibility studies served to characterize the device's performance chemically and biologically.
9. How the Ground Truth for the Training Set Was Established:
As noted above, the device is a PCR-based NAAT, not an AI/ML system, so a "training set" for an algorithm in the traditional sense is not discussed. The development and optimization of the assay's chemical and molecular components would have been guided by fundamental scientific principles and laboratory testing, rather than an algorithmic training process using labeled data. Benchmarking for analytical characteristics (like LoD) would involve preparing samples with known concentrations of organisms.
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