(76 days)
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.
§ 866.3981 Device to detect and identify nucleic acid targets in respiratory specimens from microbial agents that cause the SARS-CoV-2 respiratory infection and other microbial agents when in a multi-target test.
(a)
Identification. A device to detect and identify nucleic acid targets in respiratory specimens from microbial agents that cause the SARS-CoV-2 respiratory infection and other microbial agents when in a multi-target test is an in vitro diagnostic device intended for the detection and identification of SARS-CoV-2 and other microbial agents when in a multi-target test in human clinical respiratory specimens from patients suspected of respiratory infection who are at risk for exposure or who may have been exposed to these agents. The device is intended to aid in the diagnosis of respiratory infection in conjunction with other clinical, epidemiologic, and laboratory data or other risk factors.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The intended use in the labeling required under § 809.10 of this chapter must include a description of the following: Analytes and targets the device detects and identifies, the specimen types tested, the results provided to the user, the clinical indications for which the test is to be used, the specific intended population(s), the intended use locations including testing location(s) where the device is to be used (if applicable), and other conditions of use as appropriate.
(2) Any sample collection device used must be FDA-cleared, -approved, or -classified as 510(k) exempt (standalone or as part of a test system) for the collection of specimen types claimed by this device; alternatively, the sample collection device must be cleared in a premarket submission as a part of this device.
(3) The labeling required under § 809.10(b) of this chapter must include:
(i) A detailed device description, including reagents, instruments, ancillary materials, all control elements, and a detailed explanation of the methodology, including all pre-analytical methods for processing of specimens;
(ii) Detailed descriptions of the performance characteristics of the device for each specimen type claimed in the intended use based on analytical studies including the following, as applicable: Limit of Detection, inclusivity, cross-reactivity, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, precision, reproducibility, and clinical studies;
(iii) Detailed descriptions of the test procedure(s), the interpretation of test results for clinical specimens, and acceptance criteria for any quality control testing;
(iv) A warning statement that viral culture should not be attempted in cases of positive results for SARS-CoV-2 and/or any similar microbial agents unless a facility with an appropriate level of laboratory biosafety (
e.g., BSL 3 and BSL 3+, etc.) is available to receive and culture specimens; and(v) A prominent statement that device performance has not been established for specimens collected from individuals not identified in the intended use population (
e.g., when applicable, that device performance has not been established in individuals without signs or symptoms of respiratory infection).(vi) Limiting statements that indicate that:
(A) A negative test result does not preclude the possibility of infection;
(B) The test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician;
(C) There is a risk of incorrect results due to the presence of nucleic acid sequence variants in the targeted pathogens;
(D) That positive and negative predictive values are highly dependent on prevalence;
(E) Accurate results are dependent on adequate specimen collection, transport, storage, and processing. Failure to observe proper procedures in any one of these steps can lead to incorrect results; and
(F) When applicable (
e.g., recommended by the Centers for Disease Control and Prevention, by current well-accepted clinical guidelines, or by published peer-reviewed literature), that the clinical performance may be affected by testing a specific clinical subpopulation or for a specific claimed specimen type.(4) Design verification and validation must include:
(i) Detailed documentation, including performance results, from a clinical study that includes prospective (sequential) samples for each claimed specimen type and, as appropriate, additional characterized clinical samples. The clinical study must be performed on a study population consistent with the intended use population and compare the device performance to results obtained using a comparator that FDA has determined is appropriate. Detailed documentation must include the clinical study protocol (including a predefined statistical analysis plan), study report, testing results, and results of all statistical analyses.
(ii) Risk analysis and documentation demonstrating how risk control measures are implemented to address device system hazards, such as Failure Modes Effects Analysis and/or Hazard Analysis. This documentation must include a detailed description of a protocol (including all procedures and methods) for the continuous monitoring, identification, and handling of genetic mutations and/or novel respiratory pathogen isolates or strains (
e.g., regular review of published literature and periodic in silico analysis of target sequences to detect possible mismatches). All results of this protocol, including any findings, must be documented and must include any additional data analysis that is requested by FDA in response to any performance concerns identified under this section or identified by FDA during routine evaluation. Additionally, if requested by FDA, these evaluations must be submitted to FDA for FDA review within 48 hours of the request. Results that are reasonably interpreted to support the conclusion that novel respiratory pathogen strains or isolates impact the stated expected performance of the device must be sent to FDA immediately.(iii) A detailed description of the identity, phylogenetic relationship, and other recognized characterization of the respiratory pathogen(s) that the device is designed to detect. In addition, detailed documentation describing how to interpret the device results and other measures that might be needed for a laboratory diagnosis of respiratory infection.
(iv) A detailed device description, including device components, ancillary reagents required but not provided, and a detailed explanation of the methodology, including molecular target(s) for each analyte, design of target detection reagents, rationale for target selection, limiting factors of the device (
e.g., saturation level of hybridization and maximum amplification and detection cycle number, etc.), internal and external controls, and computational path from collected raw data to reported result (e.g., how collected raw signals are converted into a reported signal and result), as applicable.(v) A detailed description of device software, including software applications and hardware-based devices that incorporate software. The detailed description must include documentation of verification, validation, and hazard analysis and risk assessment activities, including an assessment of the impact of threats and vulnerabilities on device functionality and end users/patients as part of cybersecurity review.
(vi) For devices intended for the detection and identification of microbial agents for which an FDA recommended reference panel is available, design verification and validation must include the performance results of an analytical study testing the FDA recommended reference panel of characterized samples. Detailed documentation must be kept of that study and its results, including the study protocol, study report for the proposed intended use, testing results, and results of all statistical analyses.
(vii) For devices with an intended use that includes detection of Influenza A and Influenza B viruses and/or detection and differentiation between the Influenza A virus subtypes in human clinical specimens, the design verification and validation must include a detailed description of the identity, phylogenetic relationship, or other recognized characterization of the Influenza A and B viruses that the device is designed to detect, a description of how the device results might be used in a diagnostic algorithm and other measures that might be needed for a laboratory identification of Influenza A or B virus and of specific Influenza A virus subtypes, and a description of the clinical and epidemiological parameters that are relevant to a patient case diagnosis of Influenza A or B and of specific Influenza A virus subtypes. An evaluation of the device compared to a currently appropriate and FDA accepted comparator method. Detailed documentation must be kept of that study and its results, including the study protocol, study report for the proposed intended use, testing results, and results of all statistical analyses.
(5) When applicable, performance results of the analytical study testing the FDA recommended reference panel described in paragraph (b)(4)(vi) of this section must be included in the device's labeling under § 809.10(b) of this chapter.
(6) For devices with an intended use that includes detection of Influenza A and Influenza B viruses and/or detection and differentiation between the Influenza A virus subtypes in human clinical specimens in addition to detection of SARS-CoV-2 and similar microbial agents, the required labeling under § 809.10(b) of this chapter must include the following:
(i) Where applicable, a limiting statement that performance characteristics for Influenza A were established when Influenza A/H3 and A/H1-2009 (or other pertinent Influenza A subtypes) were the predominant Influenza A viruses in circulation.
(ii) Where applicable, a warning statement that reads if infection with a novel Influenza A virus is suspected based on current clinical and epidemiological screening criteria recommended by public health authorities, specimens should be collected with appropriate infection control precautions for novel virulent influenza viruses and sent to State or local health departments for testing. Viral culture should not be attempted in these cases unless a BSL 3+ facility is available to receive and culture specimens.
(iii) Where the device results interpretation involves combining the outputs of several targets to get the final results, such as a device that both detects Influenza A and differentiates all known Influenza A subtypes that are currently circulating, the device's labeling must include a clear interpretation instruction for all valid and invalid output combinations, and recommendations for any required followup actions or retesting in the case of an unusual or unexpected device result.
(iv) A limiting statement that if a specimen yields a positive result for Influenza A, but produces negative test results for all specific influenza A subtypes intended to be differentiated (
i.e., H1-2009 and H3), this result requires notification of appropriate local, State, or Federal public health authorities to determine necessary measures for verification and to further determine whether the specimen represents a novel strain of Influenza A.(7) If one of the actions listed at section 564(b)(1)(A) through (D) of the Federal Food, Drug, and Cosmetic Act occurs with respect to an influenza viral strain, or if the Secretary of Health and Human Services determines, under section 319(a) of the Public Health Service Act, that a disease or disorder presents a public health emergency, or that a public health emergency otherwise exists, with respect to an influenza viral strain:
(i) Within 30 days from the date that FDA notifies manufacturers that characterized viral samples are available for test evaluation, the manufacturer must have testing performed on the device with those influenza viral samples in accordance with a standardized protocol considered and determined by FDA to be acceptable and appropriate.
(ii) Within 60 days from the date that FDA notifies manufacturers that characterized influenza viral samples are available for test evaluation and continuing until 3 years from that date, the results of the influenza emergency analytical reactivity testing, including the detailed information for the virus tested as described in the certificate of authentication, must be included as part of the device's labeling in a tabular format, either by:
(A) Placing the results directly in the device's labeling required under § 809.10(b) of this chapter that accompanies the device in a separate section of the labeling where analytical reactivity testing data can be found, but separate from the annual analytical reactivity testing results; or
(B) In a section of the device's label or in other labeling that accompanies the device, prominently providing a hyperlink to the manufacturer's public website where the analytical reactivity testing data can be found. The manufacturer's website, as well as the primary part of the manufacturer's website that discusses the device, must provide a prominently placed hyperlink to the website containing this information and must allow unrestricted viewing access.