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The BD CTGCTV2 assay incorporates automated DNA extraction and real-time polymerase chain reaction (PCR) for the direct, qualitative detection of DNA from:

• Chlamydia trachomatis (CT)
• Neisseria gonorrhoeae (GC)
• Trichomonas vaginalis (TV)

The assay may be used for detection of CT, GC and/or TV DNA in patient- or clinician-collected vaginal swab specimens (in a clinical setting) and male and female urine specimens. The assay may also be used for the detection of CT and GC DNA in endocervical swab and Liquid-Based Cytology (LBC) specimens in ThinPrep® PreservCyt® Solution using an aliquot that is removed prior to processing for the ThinPrep® Pap test. The assay may also be used for the detection of CT and GC DNA in clinician-collected rectal and oropharyngeal swab specimens.

The assay is indicated for use with asymptomatic and symptomatic individuals to aid in the diagnosis of chlamydial, gonococcal, and/or trichomoniasis urogenital disease and chlamydial and gonococcal extragenital infection.

The BD CTGCTV2 assay is available for use with the BD MAX™ System (urogenital specimens) or the BD COR™ System (urogenital and extragenital specimens), as described above.

The BD CTGCTV2 assay, performed on the BD COR™ System (hereafter referred to as BD CTGCTV2), is designed for use with the applicable BD Molecular specimen collection and transport devices for male and female urine, rectal swabs, oropharyngeal swabs, vaginal swabs, endocervical swabs, and LBC specimens (PreservCyt®). Specimens are collected and transported to the testing laboratory using their respective transport devices under conditions of time and temperature that have been determined to maintain the integrity of the target nucleic acids.

The BD COR™ MX Instrument, when combined with the BD COR™ PX Instrument, is to be used for automated sample preparation, extraction, and purification of nucleic acids from multiple specimen types, as well as the automated amplification and detection of target nucleic acid sequences by fluorescence-based real-time PCR for simultaneous and differential detection of Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

The BD CTGCTV2 assay extraction reagents are dried in 96-well microtiter plates that contain binding magnetic affinity beads and Sample Processing Control (SPC). Each tube is capable of binding and eluting sample nucleic acids. The SPC monitors the integrity of the reagents and the process steps involved in DNA extraction, amplification and detection, as well as for the presence of potential assay inhibitors.

The BD CTGCTV2 assay liquid reagent plate includes Wash, Elution and Neutralization buffers. The beads (described above), together with the bound nucleic acids, are washed and the nucleic acids are eluted by a combination of heat and pH. When performed on BD COR™ System, there is an additional buffer to rehydrate the dried extraction mix. Eluted DNA is neutralized and transferred to the Amplification reagent (described below) to rehydrate the PCR reagents. After reconstitution, the BD COR™ System dispenses a fixed volume of PCR-ready solution containing extracted nucleic acids into the BD PCR Cartridge. Microvalves in the BD PCR Cartridge are sealed by the system prior to initiating PCR in order to contain the amplification mixture and thus prevent evaporation and contamination.

The BD CTGCTV2 assay is comprised of two targets for Chlamydia trachomatis (detected on the same optical channel), two targets for Neisseria gonorrhoeae (detected on two different optical channels) and one target for Trichomonas vaginalis (detected on one optical channel). Only one Chlamydia trachomatis target is required to be positive in order to report a positive result. Both Neisseria gonorrhoeae targets are required to be positive in order to report a positive result.

The amplified DNA targets are detected using hydrolysis (TaqMan®) probes, labeled at one end with a fluorescent reporter dye (fluorophore), and at the other end, with a quencher moiety. Probes labeled with different fluorophores are used to detect the target analytes in different optical channels of the BD COR™ System. When the probes are in their native state, the fluorescence of the fluorophore is quenched due to its proximity to the quencher. However, in the presence of target DNA, the probes hybridize to their complementary sequences and are hydrolyzed by the 5'-3' exonuclease activity of the DNA polymerase as it synthesizes the nascent strand along the DNA template. As a result, the fluorophores are separated from the quencher molecules and fluorescence is emitted. The BD COR™ System monitors these signals at each cycle of the PCR and interprets the data at the end of the reaction to provide qualitative test results for each analyte (i.e., positive or negative).

The provided FDA 510(k) clearance letter and summary for the BD CTGCTV2 assay detail its performance in detecting Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) in extragenital specimens (rectal and oropharyngeal swabs).

Here's an analysis based on your request:

Acceptance Criteria and Reported Device Performance

The acceptance criteria for the BD CTGCTV2 assay are implicitly demonstrated through its clinical performance results, where the assay's sensitivity (Positive Percent Agreement - PPA) and specificity (Negative Percent Agreement - NPA) for extragenital specimens are compared against a Composite Comparator Algorithm (CCA). The FDA's clearance indicates that these performance metrics met the necessary standards for substantial equivalence.

Table of Acceptance Criteria and Reported Device Performance:

While explicit numerical acceptance criteria (e.g., "PPA must be >= X%") are not directly stated in the provided text, the reported performance measures are the ones that met the FDA's requirements for clearance.

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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.

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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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).

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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The NeuMoDx CT/NG Assay 2.0, as implemented on the NeuMoDx 96 Molecular System and NeuMoDx 288 Molecular System, is an automated, qualitative test for the direct detection of Chlamydia trachomatis (CT) and or Neisseria gonorrhoeae (NG) DNA as an aid in the diagnosis of chlamydial and gonococcal urogenital disease in symptomatic and asymptomatic individuals. The Assay utilizes real-time Polymerase Chain Reaction (PCR) and may be used to test male and female urine, and self-collected vaginal swab specimens (collected in a clinical setting).

The NeuMoDx CT/NG Assay 2.0 is an automated in vitro diagnostic test for the direct detection of Chlamydia trachomatis and Neisseria gonorrhoeae (CT/NG) DNA from asymptomatic and symptomatic patient specimens. The assay utilizes real-time polymerase chain reaction (PCR) for the amplification of CT and/or NG DNA and fluorogenic targetspecific TaqMan probes for the detection of the amplified DNA. At the end of the test, a determination of the presence/absence of CT and/or NG DNA in the specimen is automatically made based on the amplification status of the CT and/or NG DNA and/or Sample Process Control sequences using pre-established decision criteria. The NeuMoDx CT/NG Assay 2.0 is intended as an aid to diagnose CT and NG infections in symptomatic or asymptomatic individuals, but not to guide or monitor treatment for CT and NG infections. Concomitant cultures may be necessary to recover organisms for epidemiological typing or for further susceptibility testing.

The NeuMoDx CT/NG Assay 2.0 is an automated, qualitative test for the direct detection of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) DNA, designed to aid in the diagnosis of chlamydial and gonococcal urogenital disease in symptomatic and asymptomatic individuals.

Here's an analysis of its acceptance criteria and the study proving its performance:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for sensitivity and specificity are not explicitly stated as distinct acceptance criteria in the provided text. However, the FDA review process implies that the observed performance must be deemed acceptable. We will present the observed clinical performance as the reported device performance.

Chlamydia trachomatis (CT) Performance

Neisseria gonorrhoeae (NG) Performance

2. Sample Size Used for the Test Set and Data Provenance

• Test Set Sample Size:
  • Male Urine (CT): 1691
  • Male Urine (NG): 1698
  • Female Urine (CT): 2007
  • Female Urine (NG): 2006
  • Self-Collected Vaginal Swabs (SCVS) (CT): 2016
  • Self-Collected Vaginal Swabs (SCVS) (NG): 2016
• Data Provenance: The study was a "multicenter, pivotal, prospective urogenital specimen collection study" conducted at "14 geographically and demographically diverse U.S. sites."

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The ground truth was established by a "patient infected status (PIS) algorithm" based on results from two FDA-cleared, legally marketed Nucleic Acid Amplification Tests (NAATs). The text does not mention the involvement of human experts (e.g., radiologists, clinicians) for establishing the ground truth directly. It relies on the performance of existing, cleared diagnostic devices.

4. Adjudication Method for the Test Set

The adjudication method was a pre-specified patient infected status (PIS) algorithm rather than human expert adjudication:

• Female PIS: Established from the results of female urine (FU) and clinician-collected vaginal swab (CCVS) specimens tested by two FDA-cleared NAAT comparator assays. Females were classified as infected if at least one positive result was obtained by each assay. Any other combination was considered non-infected.
• Male PIS: Established using urine results from two FDA-cleared comparator NAATs. If the male urine results were conflicting (one positive, one negative), a third FDA-cleared NAAT method was performed as a tie-breaker to adjudicate male infection status.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance

No MRMC comparative effectiveness study was done. The study evaluated the standalone performance of the NeuMoDx CT/NG Assay 2.0 against a PIS algorithm and did not involve human readers interpreting results with or without AI assistance.

6. If a Standalone (i.e., Algorithm Only Without Human-in-the-Loop Performance) Was Done

Yes, a standalone performance study was done. The clinical performance characteristics (sensitivity and specificity) were established by comparing the results of the NeuMoDx CT/NG Assay 2.0 (an automated molecular test, essentially an algorithm-only device in its interpretation of PCR data) directly to the patient infected status algorithm. No human interpretation of the device's output and subsequent diagnosis was explicitly included in the reported performance metrics.

7. The Type of Ground Truth Used

The type of ground truth used was an expert consensus (of NAATs) / composite reference standard, referred to as a "patient infected status (PIS) algorithm," which was derived from the results of multiple (two, sometimes three) FDA-cleared, legally marketed Nucleic Acid Amplification Tests (NAATs).

8. The Sample Size for the Training Set

The document does not explicitly state a training set sample size. This device is a diagnostic assay (molecular test), not typically an AI/machine learning algorithm that undergoes a distinct training phase in the same way an image recognition AI would. The "training" or development of the assay (e.g., primer design, cutoff optimization) would have utilized various analytical studies, but a 'training set' in the context of machine learning is not reported here.

9. How the Ground Truth for the Training Set Was Established

As noted above, a distinct "training set" with ground truth established for it in the context of machine learning is not described. The assay's analytical performance (e.g., Limit of Detection, linearity, exclusivity) was characterized using contrived samples (spiked with known concentrations of CT/NG) and known negative samples. For example, the LoD was determined by testing separate dilutions of CT elementary bodies and NG cells in negative matrices, confirming 95% positivity. Inclusivity and cross-reactivity studies used known strains and organisms.

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The Visby Medical Sexual Health Test is a single-use (disposable), fully-integrated, automated Polymerase Chain Reaction (PCR) in vitro diagnostic test intended for use in point-of-care or clinical laboratory settings for the rapid detection and differentiation of DNA from Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in self-collected female vaginal swab specimens using the Visby Medical Sexual Health Vaginal Specimen Collection Kit in a health care setting. The test results are to aid in the diagnosis of symptomatic infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

The Visby Medical Sexual Health Test (Visby Test) is a single-use (disposable), fully integrated, rapid, compact device containing a PCR-based assay for direct qualitative detection and differentiation of DNA from CT, NG, and TV. The test system includes the Visby Medical Sexual Health device, the Visby Medical power supply, the Visby Medical Vaginal Specimen Collection kit, and fixed-volume transfer pipettes. The device processes self-collected vaginal swab samples by automatically performing all steps required to complete lysis, polymerase chain reaction, and amplicon detection.

The patient uses the Visby Medical Vaginal Specimen Collection Kit to self-collect a vaginal specimen with the provided flocked swab, and then the patient elutes the specimen into the Visby Medical Collection Media. The test operator transfers the collection media containing the patient specimen into the sample port of the device using the provided fixed-volume pipette where it rehydrates a lyophilized internal process control. The sample enters a lysis module, where the DNA of the sample and the internal process control are extracted using a combination of chemical lysis and high temperature. The extracted DNA enters a mixing chamber where it rehydrates lyophilized PCR reagents, followed by thermocycling to amplify target DNA. If present, the amplified pathogen target (CT, NG, and/or TV) and internal process control hybridize to specific probes located on a flow channel. Detection of the target-specific PCR product is accomplished via an enzyme-linked colorimetric assay using streptavidin bound horseradish peroxidase (HRP) and a colorimetric substrate that forms a purple precipitate. Test results can be expected in approximately 30 minutes: a green check mark will appear, and a purple color will appear in the "Results Valid" spot, indicating a valid test. A purple spot adjacent to "Chlamydia," "Gonorrhea," and/or "Trichomoniasis" signifies the presence of amplified CT, NG, and/or TV DNA in the sample.

Vaginal self-collection kits containing a tube of collection media compatible with the Sexual Health test and a collection swab are also packaged separately. External controls recommended in the product labeling are commercially available from a different manufacturer.

Here's a breakdown of the acceptance criteria and study information based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state formal acceptance criteria in terms of specific PPA/NPA thresholds for substantial equivalence to the predicate device. Instead, the studies presented aim to demonstrate "comparability" or "equivalence" to the predicate device (Visby Medical Sexual Health Click Test, K200748/CW200003). Therefore, the reported performance is compared directly against the predicate where applicable.

Based on the "Clinical Performance of the Visby Test compared to the Click test performed by untrained operators" (Table 3) and "Performance of Visby Test Compared to Click Test - Clinical Specimens" (Table 4), the reported device performance is:

Note: The acceptance criteria for the LoD comparison was explicitly stated: "The LoD values were determined to be equivalent if the lowest concentrations of organism with at least 19/20 detection rate from the two devices were within 3-fold of each other." As seen in Table 1, this criterion was met for all organisms.

2. Sample Size Used for the Test Set and Data Provenance

• LoD Comparison: Not explicitly stated as a "test set" in the traditional sense for PPA/NPA. For each LoD multiple, 20 Visby devices and 20 Click devices were tested. The data provenance appears to be laboratory-generated (spiked samples in negative pooled clinical vaginal sample).
• Reproducibility Study: Seven (7) panel members (negative, low positive, moderate positive for CT, NG, TV) were used. Each panel member was tested by 6 operators (2 per site) three times each day over 6 non-consecutive days, across 3 reagent lots. This results in $7 \times 6 \times 3 \times 6 = 756$ individual test results reported (though the table summarizes 108 tests per panel member for overall agreement, implying 108 replicates per panel across sites/operators/days). Data provenance is likely laboratory-contrived samples (cultured organisms in negative pooled clinical vaginal swab matrix).
• Multicenter Study with Untrained Operators:
  • Sample Size: 102 samples initially selected; 1 was excluded, so 101 samples were included in the final analysis (30 CT positive, 20 NG positive, 30 TV positive, 33 negative based on comparator results, though the sum of these is 113, implying some overlap or specific positivity counts within the 101 total).
  • Data Provenance: De-identified, frozen, self-collected vaginal swab specimens that are a subset of patient samples previously characterized in the clinical study for the Click Test. This indicates retrospective human clinical data from the U.S. (implied by FDA submission context, though not explicitly stated for this particular subset).
• Single Center Study with Trained Operators:
  • Sample Size: 359 specimens initially; 1 excluded due to insufficient volume, 7 excluded due to retest issues. Final analysis included 351 specimens.
  • Data Provenance: De-identified, frozen, archived self-collected vaginal swab specimens in Visby Medical Collection Media. These included specimens from the original clinical study of the Click Test and from two other previous Visby Medical studies. This indicates retrospective human clinical data, likely from the U.S.
• Contrived Specimens Spiked at Low Organism Concentrations:
  • Sample Size: 80 contrived samples (20 CT positive, 20 NG positive, 20 TV positive, and 20 negative).
  • Data Provenance: Laboratory-generated, spiked samples using individual clinical matrices.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The document mentions that for the Multicenter Study and Single Center Study:

• The samples were "previously characterized in the clinical study for the Click Test" and "based on comparator results from the clinic study for Click Test."
• "TV PIS (based on the original clinical study for Click Test) for all seven specimens were negative."

This strongly implies that the ground truth for these clinical test sets was established during the clinical studies for the predicate device (Click Test). The report for the current device (Visby Test) does not detail the specific number or qualifications of experts for establishing the ground truth for these retrospective samples, as that would have been documented in the original predicate device's submission. It refers to "comparator results," which typically means a highly sensitive and specific reference method (e.g., PCR with bidirectional sequencing, culture followed by definitive identification) performed and interpreted by qualified laboratory personnel, rather than a panel of clinical experts adjudicating cases for complex imaging or clinical diagnoses.

For the LoD and Contrived samples studies, the "ground truth" is known by design, as the samples are deliberately spiked with known concentrations of organisms.

4. Adjudication Method for the Test Set

The document does not describe a formal adjudication method (like 2+1 or 3+1) for establishing the ground truth in the context of clinical samples.

• For the multicenter and single-center clinical studies, the reference standard (ground truth) was based on "comparator results" from the original clinical studies of the predicate device. This typically implies a highly accurate lab-based method.
• For the reproducibility, LoD, and contrived sample studies, the ground truth was known by design (known presence/absence and concentration of spiked organisms).

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

This device is an in vitro diagnostic (IVD) test that directly detects nucleic acids via PCR and provides a visually interpreted result. It is not an AI-based imaging analysis tool or a system that "assists human readers" in the way an MRMC study would typically evaluate for AI in radiology or pathology. The "operators" are interpreting the device's output (presence of a purple spot), not interpreting complex data that AI might enhance. Therefore, an MRMC comparative effectiveness study for human readers with and without AI assistance is not applicable and was not done.

The studies performed evaluate the performance of the device itself when operated by different user groups (trained vs. untrained) and compared to a predicate device.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

The Visby Medical Sexual Health Test is a fully integrated, automated PCR diagnostic test that provides a visual result (purple spot). The results are then visually interpreted by an operator ("Operator visually interprets test results" - pg 6). While the internal PCR process is automated, the final "reading" is done by a human looking at the colorimetric output. Therefore, it's not a purely "algorithm-only" device without human intervention for result interpretation. However, the performance data presented (PPA/NPA) reflects the device's accuracy in producing the correct visual output, as subsequently interpreted by a human operator. The studies demonstrate the performance of the device system including human interpretation in different use environments.

7. The Type of Ground Truth Used

• Clinical Comparison Studies (Multicenter and Single Center): The ground truth was established by "comparator results" from the original clinical studies of the predicate device (Visby Medical Sexual Health Click Test). This typically refers to a highly accurate laboratory-based reference method, such as a laboratory-developed test (LDT) using PCR with sequencing confirmation, or culture followed by definitive identification, considered the gold standard for detecting these pathogens.
• LoD, Reproducibility, and Contrived Samples Studies: The ground truth was established by design, using cultured organisms spiked at known concentrations into negative clinical matrices.

8. The Sample Size for the Training Set

The document describes performance data for the Visby Medical Sexual Health Test, which is an "updated version of the Visby Medical Sexual Health Click test (Click Test, the predicate)." It explicitly states that "The Visby Test has no changes to the PCR primer and probe sequences, reagent formulations, detection method, or result interpretations."

Since this is an updated version of an existing device with no changes to the core diagnostic method (PCR primers, probes, detection), it's highly unlikely that a separate "training set" in the context of machine learning model development was used for this specific device. The document focuses on demonstrating equivalence to the predicate device. If the predicate device (Click Test) involved any form of algorithm development requiring a training set, that would have been part of its original 510(k) submission (K200748/CW200003). For the current submission, the studies are primarily verification and validation, showing that the new manufacturing process and simplified user interface do not negatively impact performance compared to the predicate.

Therefore, a sample size for a training set for the Visby Medical Sexual Health Test is not applicable / not provided in this document.

9. How the Ground Truth for the Training Set Was Established

As mentioned in point 8, a "training set" for an algorithm is not described or applicable to the type of update this device represents. If the predicate device (Click Test) had a training set, the ground truth for that would have been established according to its original clearance. This document focuses on demonstrating equivalence of the updated physical device.

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The Alinity m STI Assay is an in vitro polymerase chain reaction (PCR) assay for use with the automated Alinity m System for the direct, qualitative detection and differentiation of ribosomal RNA from Chlamydia trachomatis (CT), DNA from Neisseria gonorrhoeae (NG), ribosomal RNA from Trichomonas vaginalis (TV), and ribosomal RNA from Mycoplasma genitalium (MG), to aid in the diagnosis of disease(s) caused by infection from these organisms. The assay may be used to test the following specimens from symptomatic and asymptomatic individuals for the following analytes:

• . CT: vaginal swabs (clinician-collected and self-collected in a clinical setting). endocervical swabs, gynecological specimens in ThinPrep PreservCyt Solution, female urine, male urine, oropharyngeal swabs, and rectal swabs
• . NG: vaginal swabs (clinician-collected and self-collected in a clinical setting), endocervical swabs, gynecological specimens in ThinPrep PreservCyt Solution, female urine, male urine, oropharyngeal swabs, and rectal swabs
• . TV: vaginal swabs (clinician-collected and self-collected in a clinical setting). endocervical swabs, gynecological specimens in ThinPrep PreservCyt Solution, female urine, and male urine
• . MG: vaginal swabs (clinician-collected and self-collected in a clinical setting), endocervical swabs, and male urine

A vaginal swab (self-collected or clinician-collected) is the preferred specimen type for MG testing in females due to the higher clinical sensitivity compared to endocervical swabs. If endocervical swab specimens test negative, testing with a vaginal swab may be indicated if M. genitalium infection is suspected.

The Alinity m STI Assay utilizes real time PCR to amplify and detect Chlamydia trachomatis (CT) ribosomal RNA sequences, Neisseria gonorrhoeae (NG) genomic DNA sequences, Trichomonas vaginalis (TV) ribosomal RNA sequences, Mycoplasma genitalium (MG) ribosomal RNA sequences, and human genomic DNA sequences that have been extracted from endocervical swab specimens, vaginal swab specimens, oropharyngeal swab specimens, rectal swab specimens, male and female urine specimens, and gynecological specimens preserved in PreservCyt Solution. Endocervical swab, vaginal swab, oropharyngeal swab, rectal swab, and urine specimens are collected with the Alinity m multi-Collect Specimen Transport Kit. PreservCyt specimens are transferred to a transport tube for processing on the Alinity m System.

This device is similar to the predicate device originally cleared (K202977). It does not introduce any changes to the Alinity m STI Assay reagents, sample processing, assay procedure, and data reduction. This device is updating the previous FDA-cleared Intended Use (K202977) to include claims for the following specimens for the following analytes:

• CT: Gynecological specimens in ThinPrep PreservCyt Solution, female urine .
• NG: Female urine

Two studies were initiated to support these claims (refer to Section 1.7.2.) This supplemental data was used with data previously obtained from the Alinity m STI Assay clinical testing studies submitted in K202977.

The steps of the Alinity m STI Assay consist of sample preparation. RT-PCR assembly, amplification/detection, and result calculation and reporting. All stages of the Alinity m STI Assay procedure are executed automatically by the Alinity m System. No intermediate processing or transfer steps are performed by the user. The Alinity m System is designed to be a random-access analyzer that can perform the Alinity m STI Assay in parallel with other Alinity m assays on the same instrument.

The Alinity m STI Assay is an in vitro diagnostic device for the qualitative detection and differentiation of nucleic acids from Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Trichomonas vaginalis (TV), and Mycoplasma genitalium (MG) in various human specimen types. The device operates on the automated Alinity m System and utilizes real-time Polymerase Chain Reaction (PCR) technology. This submission primarily focuses on supporting expanded claims for specific analytes and specimen types: CT in gynecological specimens in ThinPrep PreservCyt Solution and female urine, and NG in female urine.

Here's a breakdown of the acceptance criteria and study details:

1. Table of Acceptance Criteria and Reported Device Performance:

The document doesn't explicitly state "acceptance criteria" for the clinical performance in terms of specific thresholds (e.g., minimum PPA/NPA). Instead, it presents the Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) values with 95% Confidence Intervals (CI) as the primary performance metrics, demonstrating the device's accuracy against a Composite Comparator Algorithm (CCA).

Note: The table is constructed based on the "specimen-specific positive and negative agreement" data. The document does not provide specific acceptance thresholds, but the presented performance metrics are high, demonstrating the device's effectiveness.

2. Sample Size Used for the Test Set and Data Provenance:

• CT and NG in Female Urine:
  • Sample Size: A total of 2,798 female subjects were enrolled. 2,785 CT results and 2,784 NG results were used in the analysis after exclusions due to missing/indeterminate CCA results.
  • Data Provenance: The study was a multicenter clinical study conducted in the United States. Subjects provided urine specimens. The data includes both symptomatic and asymptomatic individuals.
• CT in PreservCyt Specimens:
  • Sample Size: 1,939 specimens from a multicenter clinical study were included in the analysis.
  • Data Provenance: The study was a multicenter clinical study conducted in the United States. Female subjects provided gynecological specimens collected in PreservCyt Solution.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:

The ground truth was established using a clinical comparator method, not individual experts.

• Ground Truth Method: A Composite Comparator Algorithm (CCA) was used.
• Details: For each subject, a CCA was determined for each analyte based on the combined results from commercially available nucleic acid amplification tests (NAATs).
  • For the female urine study (CT and NG), comparator assays included 3 commercially available NAATs. Specimens were initially tested with 2 NAATs. If they disagreed or a result was missing/indeterminate, a third tiebreaker NAAT was used.
  • For the PreservCyt study (CT), specimens were tested with up to 3 comparator NAATs. Similar to the urine study, specimens were initially tested with 2 NAATs, and a third was used as a tiebreaker if needed.
• Qualifications of Experts: The document does not mention the use of human experts or their qualifications for establishing ground truth. The ground truth is effectively an "expert panel of assays" (the comparator NAATs).

4. Adjudication Method for the Test Set:

• Method: A 2+1 adjudication method was employed for establishing the Composite Comparator Algorithm (CCA).
  • Description: Specimens were initially tested with two comparator NAATs.
  • If the two initial NAATs agreed (both positive or both negative), that result formed the CCA.
  • If the two initial NAATs disagreed, or if one result was missing or indeterminate, a third "tiebreaker" NAAT was used to resolve the discrepancy and establish the CCA.
  • A subject was categorized as "Positive" if at least 2 comparator assay results were positive and "Negative" if at least 2 comparator assay results were negative.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done:

No, an MRMC comparative effectiveness study was not done. The Alinity m STI Assay is an in vitro diagnostic device (IVD) that provides a qualitative result directly. Its performance is compared against a composite reference standard (CCA) derived from other NAATs, not against human readers. Therefore, the concept of human readers improving with AI assistance is not applicable in this context.

6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done:

Yes, a standalone performance study was done. The reported performance metrics (PPA and NPA) reflect the accuracy of the Alinity m STI Assay (algorithm and reagents performed on the automated Alinity m System) operating independently against the established ground truth (CCA). The device provides a direct, qualitative result without human interpretation of the algorithm's output for diagnosis.

7. The Type of Ground Truth Used:

The ground truth used was a Composite Comparator Algorithm (CCA), which is an expert consensus based on multiple FDA-cleared nucleic acid amplification tests (NAATs). These NAATs are considered the gold standard for detecting these pathogens. The CCA essentially serves as the "best available truth" when a true clinical outcome or pathological confirmation for all cases is not feasible or practical in a large-scale clinical trial.

8. The Sample Size for the Training Set:

The document does not explicitly describe a separate "training set" for the Alinity m STI Assay in the context of this 510(k) submission. This is typical for IVD devices, where the assay's design, reagent formulation, and analytical parameters are developed through internal R&D, rather than a machine learning training paradigm with a distinct training dataset for an "algorithm." The clinical studies mentioned (both the original K202977 studies and the supplemental studies) serve as validation/test sets to demonstrate the performance of the already developed assay.

9. How the Ground Truth for the Training Set Was Established:

Since a distinct "training set" in the machine learning sense is not described, the question of how its ground truth was established is not directly applicable. The Alinity m STI Assay's underlying technology (real-time PCR) and design would have been established and optimized based on known genetic sequences, analytical performance studies (e.g., analytical sensitivity, specificity), and prior knowledge of the target organisms, where ground truth sources for these developmental phases would likely include:

• Well-characterized isolates/strains: Known positive and negative biological samples.
• Synthetic nucleic acid targets: Designed to validate primer and probe performance.
• Spiked matrix samples: To assess analytical performance in relevant specimen types.

These developmental activities would precede the clinical validation studies that are the focus of this 510(k) submission.

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The Aptima Combo 2® assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal disease using the Panther® system as specified.
On the Panther system, the assay may be used to test the following specimens from symptomatic and asymptomatic individuals: clinician-collected endocervical, PreservCyt® Solution liquid Pap specimens, vaginal, throat, rectal, and male urethral swab specimens; patient collected vaginal swab specimens , and female and male urine specimens.
¹Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The Aptima Multitest Swab Specimen Collection Kit has not been evaluated for home use.

The Aptima Combo 2® assay is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection and differentiation of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) and/or Neisseria gonorrhoeae (GC) to aid in the diagnosis of chlamydial and/or gonococcal urogenital disease using the Tigris® DTS® Automated Analyzer. The assay may be used to test the following specimens from symptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; and female and male urine specimens. The assay may be used to test the following specimens from asymptomatic individuals: clinician-collected endocervical, vaginal and male urethral swab specimens; patient-collected vaginal swab specimens'; and female and male urine specimens. The assay is also intended for use with the testing of gynecological specimens, from both symptomatic and asymptomatic patients, collected in the PreservCyt® Solution.
1 Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The Aptima Multitest Swab Specimen Collection Kit is not for home use.

The Aptima Trichomonas vaginalis Assay is an in vitro qualitative nucleic acid amplification test (NAAT) for the detection of ribosomal RNA (rRNA) from Trichomonas vaginalis to aid in the diagnosis of trichomoniasis using the Panther System. The assay may be used to test the following specimens from symptomatic or asymptomatic women: clinician-collected endocervical swabs, clinician-collected vaginal swabs, and specimens collected in PreservCyt Solution.

The Aptima Trichomonas vaginalis Assay is an in vitro qualitative nucleic acid amplification test (NAAT) for the detection of ribosomal RNA (rRNA) from Trichomonas vaginalis to aid in the diagnosis of trichomoniasis using the Tigris® DTS® System. The assay may be used to test the following specimens from symptomatic or asymptomatic women: clinician-collected endocervical swabs, clinician-collected vaginal swabs, female urine specimens, and specimens collected in PreservCyt Solution.

The Aptima Combo 2 Assay (AC2) combines the technologies of target capture, TMA, and DKA. Specimens are collected and transferred into their respective specimen transport tubes. The transport solutions in these tubes release the rRNA targets and protect them from degradation during storage. When the Aptima Combo 2 Assay is performed in the laboratory, the target rRNA molecules are isolated from specimens by use of capture oligomers via target capture that utilizes magnetic microparticles. The capture oligomers contain sequences complementary to specific regions of the target molecules as well as a string of deoxyadenosine residues. A separate capture oligomer is used for each target. During the hybridization step, the sequence specific regions of the capture oligomers bind to specific regions of the target molecules. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the polydeoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecules bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification reaction inhibitors. After the target capture steps are completed, the specimens are ready for amplification.
Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The Aptima Combo 2 Assay replicates a specific region of the 23S rRNA from CT and a specific region of the 16S rRNA from GC via DNA intermediates. A unique set of primers is used for each target molecule. Detection of the rRNA amplification product sequences (amplicon) is achieved using nucleic acid hybridization. Single-stranded nucleic acid chemiluminescent probes, which are complementary to a region of each target amplicon, are labeled with different acridinium ester molecules. The updated version of the Aptima Combo 2 assay incorporates a second CT probe, complementary to a unique region of the existing CT amplicon. This tandem probe provides detection coverage for the variant strains of C. trachomatis that emerged in 2019. The labeled probes combine with amplicon to form stable hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled hybrids is measured as photon signals in a luminometer and are reported as Relative Light Units (RLU). In DKA, differences in the kinetic profiles of the CT and GC labeled probes allow for the differentiation of signal; kinetic profiles are derived from measurements of photon output during the detection read time. The chemiluminescent detection for CT signal has very rapid kinetics and has the "flasher" kinetic type. The chemiluminescent detection for GC signal is relatively slower and has the "glower" kinetic type. Assay results are determined by a cut-off based on the total RLU and the kinetic curve type.

The Aptima Trichomonas vaginalis Assay (ATV) involves the technologies of target capture, transcription-mediated amplification (TMA), and hybridization protection assay (HPA). Specimens are collected and transferred into their respective specimen transport tubes. The transport solution in these tubes releases the rRNA target and protects it from degradation during storage. When the Aptima Trichomonas vaginalis Assay is performed in the laboratory, the target rRNA is isolated from the specimens by the use of a specific capture oligomer and magnetic microparticles in a method called target capture. The capture oligomer contains a sequence complementary to a specific region of the target molecule as well as a string of deoxyadenosine residues. During the hybridization step, the sequence-specific region of the capture oligomer binds to a specific region of the target molecule. The capture oligomer:target complex is then captured out of solution by decreasing the temperature of the reaction to room temperature. This temperature reduction allows hybridization to occur between the deoxyadenosine region on the capture oligomer and the poly-deoxythymidine molecules that are covalently attached to the magnetic particles. The microparticles, including the captured target molecule bound to them, are pulled to the side of the reaction vessel using magnets and the supernatant is aspirated. The particles are washed to remove residual specimen matrix that may contain amplification inhibitors. After the target capture steps are completed, the specimens are ready for amplification.
Target amplification assays are based on the ability of complementary oligonucleotide primers to specifically anneal and allow enzymatic amplification of the target nucleic acid strands. The Hologic TMA reaction amplifies a specific region of the small ribosomal subunit from T. vaginalis via DNA and RNA intermediates and generates RNA amplicon molecules. Detection of the rRNA amplification product sequences is achieved using nucleic acid hybridization (HPA). A single stranded chemiluminescent DNA probe, which is complementary to a region of the target amplicon, is labeled with an acridinium ester molecule. The labeled DNA probe combines with amplicon to form stable RNA:DNA hybrids. The Selection Reagent differentiates hybridized from unhybridized probe, eliminating the generation of signal from unhybridized probe. During the detection step, light emitted from the labeled RNA:DNA hybrids is measured as photon signals in a luminometer and are reported as Relative Light Units (RLU).

Acceptance Criteria and Device Performance for Aptima Combo 2 Assay and Aptima Trichomonas Vaginalis Assay (RMR Probe Reagent Update)

This document describes the acceptance criteria and the studies that demonstrate the device meets those criteria, specifically concerning the manufacturing change to the Ready-Made Reagents (RMR) Probe Reagent for the Aptima Combo 2 Assay (AC2) and Aptima Trichomonas Vaginalis Assay (ATV). The core of this submission is to prove that the removal of the lyophilization step for the RMR Probe Reagent does not negatively impact assay performance compared to the previously cleared predicate devices.

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implicitly defined by demonstrating comparability to the predicate devices. The key performance metrics evaluated are Intended Use (overall agreement with expected positivity) and Limit of Detection (LoD). For clinical performance, the acceptance criteria are 100% agreement between the predicate and the modified RMR assay. For LoD, the acceptance criterion is that the RMR assay's LoD is within ½ log of the predicate assay's LoD.

2. Sample Size for the Test Set and Data Provenance

Intended Use Study:

• Aptima Combo 2 Assay (Panther): Negative and positive panels (exact number of panels or individual samples not specified, but stated to include CT positive, FI-nvCT positive, and CT/GC dual positive panels).
• Aptima Combo 2 Assay (Tigris): Negative and positive panels (exact number of panels or individual samples not specified, but stated to include CT positive, FI-nvCT positive, and CT/GC dual positive panels).
• Aptima Trichomonas Vaginalis Assay (Panther): Negative, TV positive, and TV low positive panels (exact number of panels or individual samples not specified).
• Aptima Trichomonas Vaginalis Assay (Tigris): Negative, TV positive, and TV low positive panels (exact number of panels or individual samples not specified).
• Data Provenance: Not explicitly stated, but these appear to be contrived panels (controlled positive and negative samples) rather than directly clinical specimens for this specific study.

Limit of Detection (LoD) Study:

• Aptima Combo 2 Assay (Panther & Tigris): Stocks of CT and GC organisms, and FI-nvCT in vitro transcript. These were run in negative clinical liquid pap specimens collected in PreservCyt solution (ThinPrep).
• Aptima Trichomonas Vaginalis Assay (Panther & Tigris): Stocks of TV organisms in negative clinical liquid pap specimens collected in PreservCyt solution (ThinPrep).
• Data Provenance: The base matrix used for spiking was "negative clinical liquid pap specimens," suggesting these are retrospective clinical samples from an unspecified origin, used in a prospective manner for LoD determination.

Clinical Performance Study:

• Aptima Combo 2 Assay (Panther): 219 remnant clinical swab specimens.
• Aptima Combo 2 Assay (Tigris): 200 remnant clinical swab specimens.
• Data Provenance: "remnant clinical swab specimens". This indicates these are retrospective samples collected from prior clinical testing, with the country of origin not specified.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The ground truth for these studies is established by the performance of the predicate AC2 assay or ATV assay, which was previously cleared by the FDA. The document does not describe the involvement of additional human experts for the ground truth of these specific comparability studies, as the goal is to show the new RMR Probe Reagent performs equivalently to the already established predicate. The reliability of the predicate assays themselves would have been established through prior studies reviewed by the FDA, presumably involving expert consensus or validated methods.

4. Adjudication Method for the Test Set

Adjudication methods were not applicable in these studies. The assessment compares the performance of the modified AC2/ATV RMR assays directly against the predicate AC2/ATV assays. The predicate assay's result is used as the reference/ground truth for comparison. There is no mention of a separate expert adjudication process for discordant results between the predicate and the modified device in these comparability studies. In the LoD studies, the ground truth for spiked samples is defined by the known concentration of the spiked organisms/transcripts.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No MRMC comparative effectiveness study was done. This study concerns an in vitro diagnostic (IVD) device (nucleic acid amplification test) for direct detection of pathogens, not an AI-assisted diagnostic tool for human readers. Therefore, there is no human-in-the-loop performance to evaluate, and thus no effect size for human reader improvement with AI assistance.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance)

The studies presented are effectively standalone performance evaluations of the modified IVD assays. The assays are fully automated on the Panther and Tigris systems, and the results are interpreted based on predefined cut-offs (Relative Light Units and kinetic curve type). There is no human intervention in the result determination process once the assay is run. The comparison is between two versions of an automated assay.

7. Type of Ground Truth Used

• Intended Use Study: The "expected positivity results" indicate that calibrated positive and negative control panels (contrived ground truth) were used. These panels simulate clinical conditions but are created in a controlled laboratory setting.
• Limit of Detection (LoD) Study: The ground truth for LoD was spiked negative clinical specimens with known concentrations of target organisms/transcripts. This is a form of contrived ground truth based on quantitative standards.
• Clinical Performance Study: The ground truth for the clinical comparability study was the result of the predicate AC2 assay. This means the predicate assay's output was considered the reference standard, rather than an independent expert consensus or pathology review of the remnant specimens themselves for this specific comparability study. The performance of the predicate itself would have been validated against clinical outcomes or a gold standard during its initial clearance.

8. Sample Size for the Training Set

No training set is explicitly mentioned or relevant for this submission. This submission describes a manufacturing change to a reagent component of already cleared IVD assays. The assays are based on established molecular biology principles and do not involve machine learning algorithms that require a training set to "learn" patterns or make predictions. The "development activities" mentioned relate to design control and verification testing, not algorithmic training.

9. How the Ground Truth for the Training Set Was Established

As there is no training set for an algorithm, this question is not applicable.

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The BD CTGCTV2 assay incorporates automated DNA extraction and real-time polymerase chain reaction (PCR) for the direct, qualitative detection of DNA from:

• Chlamydia trachomatis (CT)
• . Neisseria gonorrhoeae (GC)
• . Trichomonas vaginalis (TV)

The assay may be used for detection of CT, GC and/or TV DNA in patient- or clinician-collected vaginal swab specimens (in a clinical setting), and male and female urine specimens. The assay may also be used for the detection of CT and GC DNA in endocervical swab and Liquid-Based Cytology (LBC) specimens in ThinPrep PreservCyt Solution using an aliquot that is removed prior to processing for the ThinPrep Pap test.

The assay is indicated for use with asymptomatic and symptomatic individuals to aid in the diagnosis of chlamydial urogenital disease, gonococcal urogenital disease and/or trichomoniasis.

The BD CTGCTV2 assay is available for use on the BD MAX System or the BD COR System.

As with the existing BD CTGCTV2 for BD MAX System, K182692, the BD COR PX/MX (BD COR) high throughput system conducts sample extraction steps to isolate and concentrate DNA which is then amplified to detect specific sequences for diagnostic purposes.

The BD COR System is designed to allow the user to place clinical specimens directly into designated transport racks to be loaded into the System. Once the specimens are loaded, the System will perform the necessary pre-analytical steps such as vortexing, aliquoting into a molecular tube with the correct diluent, sorting/grouping of the secondary samples for testing by assay, pre-warming and cooling of the sample (where required), and transport of the sample into a molecular analyzer, where extraction, amplification and detection will take place.

Additionally, the steps of ordering tests on the instrument for specific samples will be managed directly by the user interaction with the Laboratory Information System (LIS), which communicates with the instrument.

Once the clinical specimens are received in the laboratory and loaded into the transport racks, the user will not be required to directly handle the specimen again prior to result reporting and removal from the system.

Here's a breakdown of the acceptance criteria and study details for the BD CTGCTV2 assay, based on the provided document:

Acceptance Criteria and Device Performance

The core of this submission focuses on demonstrating the substantial equivalence of the BD CTGCTV2 assay when run on the BD COR System to its previously cleared performance on the BD MAX System. Therefore, the acceptance criteria are implicitly tied to demonstrating comparable analytical and clinical performance between the two platforms.

Key Performance Metrics (Implicit Acceptance Criteria) and Reported Device Performance:

Study Information: BD CTGCTV2 Assay on BD COR System

This submission pertains to the BD CTGCTV2 assay being used on the BD COR System. The key study is a clinical agreement study and analytical performance studies designed to demonstrate that the performance of the assay on the BD COR System is equivalent to its already cleared performance on the BD MAX System (K182692).

1. A table of acceptance criteria and the reported device performance:
* See table above.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective):
* Analytical Performance (Precision & Reproducibility Test Set):
* Precision (within-laboratory): 72 replicates for each target (CT, GC, TV) at each of 4 concentration levels (MP, LP, HN, TN) for PreservCyt samples and 4 concentration levels for Urine samples. Total N is not explicitly stated as a single number but is derived. For example, for CT in PreservCyt, it's 72 * 4 = 288 data points.
* Reproducibility (multi-site): For each target and concentration level, 36 replicates per site across 3 sites (36 * 3 = 108 total replicates per target/level).
* Analytical Sensitivity Confirmation: 4 panel members (A, B, C, D) created with 1.5x LoD and 3x LoD for various target organisms and strains in pooled female urine, pooled vaginal swab, and pooled PreservCyt LBC matrix. The study compared performance between BD COR and BD MAX. The exact number of replicates for each panel member for this confirmation study is not explicitly stated as a total N, but implied to be sufficient for statistical comparison (mean Ct.Scores and 95% CIs are reported).
* Cross-Contamination: 540 positive samples and 540 negative samples for a total of 1080 samples.
* Clinical Agreement Study (Test Set):
* Sample Size: 433 independent panel members.
* Provenance: "Remnant urine specimens from the previous clinical trial for BD CTGCTV2 on BD MAX as well as urine specimens obtained from both internal and external collections were used for the comparison study." This suggests a retrospective collection of remnant urine specimens combined with potentially prospective collections from internal and external sources to create the clinical panels. The country of origin is not explicitly stated, but given the FDA submission, it can be inferred to be primarily US-based or at least compliant with US regulations.

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):
* For the Precision, Reproducibility, Analytical Sensitivity, and Cross-Contamination studies: The ground truth was established by the known concentrations or presence/absence of organisms in contrived samples or spiked matrices. These are analytical studies, not clinical studies requiring expert interpretation.
* For the Clinical Agreement Study: The BD MAX System results served as the reference/ground truth. The positive or negative status of a panel member was defined by "≥2 out of 3 evaluable results obtained on the BD MAX." This is a comparator method, not direct expert consensus on patient samples. Therefore, no human experts were used to establish the ground truth for the clinical agreement study beyond the definition of the BD MAX as the reference standard.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:
* For the Clinical Agreement Study: The "ground truth" (reference comparator result from BD MAX) was established by "≥2 out of 3 evaluable results obtained on the BD MAX". This functions as a form of "consensus" or adjudication among multiple runs (3 aliquots) on the reference system.
* For the analytical studies (precision, reproducibility), ground truth was based on known concentrations, so no adjudication by a panel of experts was necessary.

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:
* No MRMC comparative effectiveness study was done. This device is an in vitro diagnostic (IVD) assay that detects nucleic acids. It's an automated molecular system, not an AI-assisted diagnostic tool that human readers would interpret. Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable here.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
* Yes, this is a standalone performance study in the context of an IVD assay. The BD CTGCTV2 assay on the BD COR System is an automated system for qualitative detection of DNA. The studies described (analytical and clinical agreement) evaluate the performance of this automated system directly, without human interpretation of its diagnostic output. The output itself (positive/negative) is the final result.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):
* Analytical Studies (Precision, Reproducibility, Cross-Contamination, Analytical Sensitivity): The ground truth was based on known concentrations of purified organisms or specific strains spiked into negative matrices. This is an analytical ground truth.
* Clinical Agreement Study: The ground truth was the result from the legally marketed predicate device, the BD MAX System, determined by a "consensus" of ≥2 out of 3 evaluable results from the BD MAX. This is a (predicate) comparator ground truth.

8. The sample size for the training set:
* The document describes studies for validation and equivalency demonstration of the BD CTGCTV2 assay on the BD COR System compared to the BD MAX System. It does not mention "training sets" in the context of machine learning or AI models.
* For IVD assays, "training" typically refers to the initial development and optimization of the assay performed by the manufacturer. The data used for this developmental phase is not typically detailed in 510(k) summaries, which focus on formal validation studies.
* The assay itself incorporates "automated DNA extraction and real-time PCR," which are well-established molecular biology techniques, not typically "trained" in the AI sense.

9. How the ground truth for the training set was established:
* As noted above, the document does not describe a "training set" in the context of an AI/machine learning model. Therefore, this question is not applicable. The development of the PCR assay and its parameters would have involved extensive laboratory work by the manufacturer, but the "ground truth" for those developmental phases would be based on well-characterized materials and samples, similar to the analytical studies described for validation.

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The Alinity m STI Assay is an in vitro polymerase chain reaction (PCR) assay for use with the automated Alinity m System for the direct, qualitative detection and differentiation of ribosomal RNA from Chlamydia trachomatis (CT), DNA from Neisseria gonorrhoeae (NG), ribosomal RNA from Trichomonas vaginalis (TV), and ribosomal RNA from Mycoplasma genitalium (MG), to aid in the diagnosis of disease(s) caused by infection from these organisms. The assay may be used to test the following specimens from symptomatic and asymptomatic individuals for the following analytes:

CT: vaginal swabs (clinician-collected and self-collected in a clinical setting), endocervical swabs, male urine, oropharyngeal swabs, and rectal swabs

NG: vaginal swabs (clinician-collected and self-collected in a clinical setting). endocervical swabs, gynecological specimens in ThinPrep PreservCyt Solution, male urine, oropharyngeal swabs, and rectal swabs

TV: vaginal swabs (clinician-collected and self-collected in a clinical setting), endocervical swabs, gynecological specimens in ThinPrep PreservCyt Solution, female urine, and male urine

MG: vaginal swabs (clinician-collected and self-collected in a clinical setting), endocervical swabs, and male urine

A vaginal swab (self-collected or clinician-collected) is the preferred specimen type for MG testing in females due to higher clinical sensitivity compared to endocervical swabs. If endocervical swab specimens test negative, testing with a vaginal swab may be indicated if M. genitalium infection is suspected.

The Alinity m STI Assay is a real time polymerase chain reaction (PCR) assay for the amplification and detection of Chlamydia trachomatis (CT) ribosomal RNA sequences, Neisseria gonorrhea (NG) genomic DNA sequences, Trichomonas vaginalis (TV) ribosomal RNA sequences, Mycoplasma genitalium (MG) ribosomal RNA sequences, and human genomic DNA sequences. The assay can be used with endocervical swab specimens, vaginal swab specimens, male and female urine specimens, gynecological specimens in ThinPrep® PreservCyt® Solution, oropharyngeal swab specimens, and rectal swab specimens. Endocervical swab, vaginal swab, oropharyngeal swab, rectal swab and urine specimens are collected with the Alinity m multi-Collect Specimen Collection Kit. PreservCyt Solution specimens are transferred to an Alinity m Transport Tube for processing on the Alinity m System.

The steps of the Alinity m STI Assay consist of sample preparation, RT-PCR assembly, amplification/detection, and result calculation and reporting. All stages of the Alinity m STI Assay procedure are executed automatically by the Alinity m System. No intermediate processing or transfer steps are performed by the user. The Alinity m System is designed to be a random-access analyzer that can perform the Alinity m STI Assay in parallel with other Alinity m assays on the same instrument.

The Alinity m STI Assay requires two separate assay specific kits as follows:

• . Alinity m STI AMP Kit, List No. 09N17-095 consisting of multi-well amplification plates containing lyophilized, unit-dose PCR amplification/detection reagents and multi-well activator plates containing liquid, unit-dose activation reagents (MgCl2, TMAC, and KCl). The intended storage condition for the Alinity m STI AMP Kit is 2℃ to 8℃.
• . Alinity m STI CTRL Kit, List No. 09N17-085 consisting of negative controls and positive controls, each supplied as liquid in single-use tubes. The intended storage condition for the Alinity m STI Control Kit is -15°C to -25°C.

Nucleic acids from specimens are extracted automatically on-board the Alinity m System using the Alinity m Sample Prep Kit 1, Alinity m Lysis Solution, Alinity m Ethanol Solution, and Alinity m Diluent Solution. The Alinity m System employs magnetic microparticle technology to facilitate nucleic acid capture, wash and elution. The resulting purified nucleic acids are then combined with the liquid unit-dose activator reagent, lyophilized unit-dose Alinity m STI amplification reagents, and Alinity m Vapor Barrier Solution, and transferred by the instrument to an amplification/detection module for reverse transcription, PCR amplification, and real-time fluorescence detection.

Assay controls are tested at or above an established minimum frequency of every 24 hours to help ensure that instrument and reagent performance remain satisfactory. During each control event, a negative control and a positive control are processed through sample preparation and RT-PCR procedures that are identical to those used for specimens. Assay controls are used to demonstrate proper sample processing and assay validity. The controls do not indicate if bacterial cells have been adequately lysed.

The Alinity m STI amplification reagents include primers and a probe that amplify and detect the single copy human gene, ß-globin. Amplification and detection of the ß-globin gene demonstrates proper sample processing and adequate sample input. In addition, an exogenous internal control (containing an armored RNA sequence) is included in the lyophilized Alinity m STI amplification reagents to assess amplification efficiency and to confirm that no PCR inhibitors are present in the sample. The cellular control and internal control are both used to demonstrate assay validity.

The Alinity m STI Assay also utilizes the following accessories:

• . Alinity m STI Assay Application Specification File, List No. 09N17-03A
• . Alinity m System and System Software, List No. 08N53-002
• Alinity m Sample Prep Kit 1, List No. 09N18-001 .
• Alinity m multi-Collect Specimen Collection Kit, List No. 09N19-010 .
• . Alinity m Tubes and Caps, List No. 09N49:
  • Alinity m Transport Tubes Pierceable Capped, List No. 09N49-010 .
  • . Alinity m Transport Tube, List No. 09N49-011
  • Alinity m Pierceable Cap, List No. 09N49-012 .
• Alinity m System Solutions, List No. 09N20: .
  • Alinity m Lysis Solution, List No. 09N20-001 .
  • Alinity m Ethanol Solution, List No. 09N20-002 .
  • Alinity m Diluent Solution, List No. 09N20-003
  • Alinity m Vapor Barrier Solution, List No. 09N20-004 •

The Abbott Alinity m STI Assay is an in vitro polymerase chain reaction (PCR) assay used with the automated Alinity m System for the direct, qualitative detection and differentiation of ribosomal RNA from Chlamydia trachomatis (CT), DNA from Neisseria gonorrhoeae (NG), ribosomal RNA from Trichomonas vaginalis (TV), and ribosomal RNA from Mycoplasma genitalium (MG), to aid in the diagnosis of sexually transmitted infections.

The acceptance criteria and the study results are detailed below:

1. Table of Acceptance Criteria and Reported Device Performance

The device performance is reported as Sensitivity (Positive Percent Agreement or PPA) and Specificity (Negative Percent Agreement or NPA). The document does not explicitly state pre-defined acceptance criteria (e.g., a specific threshold like "Sensitivity must be >= X%"). However, the reported performance values are the outcome of the clinical trials conducted to demonstrate the device's effectiveness.

Urogenital Specimens

Extragenital Specimens

2. Sample Size Used for the Test Set and Data Provenance

• Urogenital Specimens: A total of 7,099 male and female subjects were enrolled for the urogenital clinical study. Specimens were collected across 33 geographically diverse sites in the United States, including STI clinics, primary care offices, and gynecology practices. This was a prospective study. Data provenance is United States, from prospective collection.
  • Number of results used in analysis for each analyte:
    • CT: 12,903
    • NG: 15,655
    • TV: 18,843
    • MG: 12,829
• Extragenital Specimens: A total of 2,373 male and female subjects were enrolled. Specimens were previously collected and archived. Data provenance is United States, from archived specimens (retrospective).
  • Number of results used in analysis for each analyte:
    • CT (oropharyngeal): 2,316
    • CT (rectal): 2,053
    • NG (oropharyngeal): 2,312
    • NG (rectal): 2,049

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications

The document does not explicitly state the "number of experts" or their "qualifications" involved in establishing the ground truth. Instead, the ground truth was established using comparator assays, which are commercially available nucleic acid amplification tests (NAATs) and, in some cases, culture. The results from these comparator assays were combined to derive a Patient Infected Status (PIS) or Composite Comparator (CC).

4. Adjudication Method for the Test Set

• Urogenital Specimens (PIS):
  • CT or NG (Female): A minimum of 2 positive results (at least 1 from each comparator NAAT) for infection, or at least 1 comparator NAAT reported negative results for all sample types for not infected.
  • TV or MG (Female): First 2 swab comparator NAAT results both positive, or 2 of 3 swab comparator NAAT results positive (if 3rd NAAT was a tie-breaker) for infection. First 2 swab comparator NAAT results both negative, or 2 of 3 swab comparator NAAT results negative (if 3rd NAAT was a tie-breaker) for not infected.
  • CT, NG, TV, or MG (Male): A minimum of two comparator positive results for infection. If the comparator TV culture assay result was positive, the subject was categorized as infected for TV regardless of NAAT results. Two or more comparator NAAT results negative for not infected (for CT, NG, MG). For TV, negative culture AND one or more negative comparator NAATs for not infected.
• Extragenital Specimens (CC): A specimen was categorized as infected (for CT or NG) if a minimum of 2 comparator positive results were reported. It was categorized as not infected if a minimum of 2 comparator negative results was reported.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done

No, an MRMC comparative effectiveness study was not done. The study compares the Alinity m STI Assay's performance against a composite ground truth derived from multiple established comparator assays, not directly evaluating human reader performance with and without AI assistance.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

Yes, this was a standalone performance study. The Alinity m STI Assay is an automated PCR assay, and its results are directly compared to the established ground truth without involving human interpretation or modifications of its output in the primary performance analysis.

7. The Type of Ground Truth Used

The ground truth used was a Composite Comparator / Patient Infected Status (PIS/CC), derived from the combined results of multiple commercially available and clinically cleared comparator nucleic acid amplification tests (NAATs) and, for male TV, culture results.

8. The Sample Size for the Training Set

The document does not explicitly provide the sample size for the training set for the Alinity m STI Assay. The provided performance data (Sensitivity and Specificity tables) are from the validation (test) sets.

9. How the Ground Truth for the Training Set Was Established

Since the document does not provide information about a separate training set, it is assumed that the analytical studies and the design of the assay would have utilized reference materials and potentially early clinical samples for optimization and establishment of analytical performance characteristics (like LoD, inclusivity, cross-reactivity). However, specific details on how ground truth was established for a training set are not available in this document. The clinical studies described are for validation/testing, with ground truth established by comparator assays as detailed in point 4.

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For In Vitro Diagnostic Use.

The Rheonix STI TriPlex™ Assay, as performed on the Rheonix Encompass MDx® Workstation, is an automated DNA extraction and multiplex PCR amplification test system intended for the direct, qualitative detection of DNA from Chlamydia trachomatis (CT), and/or Neisseria gonorrhoeae (NG), and/or Trichomonas vaginalis (TV) in male urine specimens collected with the Rheonix Urine Specimen Collection Kit. The test is indicated to aid in the diagnosis of chlamydial urogenital disease, gonococcal urogenital disease and trichomoniasis in asymptomatic male individuals.

The Rheonix Encompass MDx® Workstation and the Rheonix STT TriPlex™ Assay are comprised of an instrument with associated hardware and accessories, disposable microfluidic CARD cartridges, master mixes and reagent components used to extract, amplify, and detect DNA using end point PCR. In addition, all male urine specimens in this system must be collected using the Rheonix Urine Specimen Collection Kit. The process is fully automated with the user intervention required only for loading and unloading the samples and disposable assay components. The Rheonix Encompass MDx Workstation's software automatically interprets test results which may be called as POS (positive), NEG (negative), or IND (indeterminate) for each of the assay's three targets. In addition, if the instrument encounters an error during the performance of the assay, it will report an ERR code. If either an IND or ERR code results, the same specimen should be reanalyzed for the presence of the target for which the indeterminate or error code occurred. Each assay has a built-in process control that assures that the individual steps of the entire process occurred properly. The user may also include external positive and/or negative controls to monitor the assay performance.

The Rheonix STI TriPlex Assay, performed on the Rheonix Encompass MDx Workstation, is an automated DNA extraction and multiplex PCR amplification test system for the direct, qualitative detection of DNA from Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), and Trichomonas vaginalis (TV) in male urine specimens.

Here's an analysis of the acceptance criteria and the study that proves the device meets them:

1. Table of Acceptance Criteria and Reported Device Performance:

The document describes the clinical performance (sensitivity and specificity) against a Patient Infection Status (PIS) derived from FDA-cleared Nucleic Acid Amplification Tests (NAATs). While explicit "acceptance criteria" are not listed as pass/fail values, the reported performance metrics serve as the demonstration that the device is fit for its intended use. For the purpose of this response, I will list the observed clinical performance as the "reported device performance," which implicitly met the FDA's criteria for substantial equivalence.

2. Sample size used for the test set and the data provenance:

• Test Set Sample Size:
  • CT and NG: 1606 evaluable male subjects.
  • TV: 1585 evaluable male subjects (out of 1586, one excluded due to invalid test result).
• Data Provenance:
  • Country of Origin: United States. Specimens were collected at 8 geographically distinct sites in the US.
  • Retrospective or Prospective: Prospective. The study enrolled both symptomatic and asymptomatic subjects, and one first-catch urine specimen was collected from each subject.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

The ground truth, referred to as "Patient Infection Status (PIS)," was established by multiple FDA-cleared Nucleic Acid Amplification Tests (NAATs), not individual human experts. The document does not specify the number or qualifications of experts involved in running these comparator NAATs or interpreting their results beyond the described adjudication method. It implies that these were standard laboratory procedures using cleared devices.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

The adjudication method used to establish the Patient Infection Status (PIS) for the test set was a 2+1 method:

• For each target (CT, NG, TV), up to three different FDA cleared NAATs were used.
• If the first two NAATs yielded concordant results (both positive or both negative), the PIS was defined accordingly.
• If the first two NAATs were not concordant, a third "tie-breaker" test was used. The PIS was then determined based on the majority rule (2 out of 3 results being either positive or negative).

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:

This device is an automated in vitro diagnostic (IVD) assay for nucleic acid detection, not an AI-assisted imaging device that involves human "readers." Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance was not applicable and not performed. The device itself provides an automated interpretation (Positive, Negative, Indeterminate, or Error).

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:

Yes, a standalone performance study was done. The entire premise of the clinical performance evaluation (Tables 15-17) is a direct comparison of the Rheonix STI TriPlex Assay's automated results (Positive, Negative) against the established Patient Infection Status (PIS). There is no mention of a human-in-the-loop component for the Rheonix system's result interpretation. The workstation's software automatically interprets test results.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

The ground truth used was molecular diagnostic consensus derived from multiple FDA-cleared Nucleic Acid Amplification Tests (NAATs). This is a common and accepted method for establishing ground truth in diagnostic studies for infectious diseases, as NAATs are highly sensitive and specific.

8. The sample size for the training set:

The document does not explicitly specify a "training set" for the clinical performance evaluation in the context of device clearance. Instead, it describes analytical and clinical performance studies demonstrating the device's capability. For an IVD like this, "training" typically refers to the development and optimization phase using internal validation data rather than a distinct, reported "training set" from a pivotal clinical trial. No sample size for a separate training set is provided in this submission summary.

9. How the ground truth for the training set was established:

As noted above, a distinct "training set" with ground truth established in the same manner as a clinical test set is not typically described for IVD device submissions in this way. The analytical performance characteristics (e.g., Limit of Detection, Inclusivity, Specificity, Interference, Carry-over) are established using contrived samples with known concentrations of target organisms and potential interfering substances, which serve as a form of "ground truth" for ensuring the assay's fundamental analytical capabilities during its development and internal validation. The clinical study then validates these capabilities in real-world patient samples against the PIS.

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