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The Aptima Trichomonas vaginalis (TV) 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 individuals: clinician-collected endocervical swabs, clinician-collected and patient-collected vaginal swabs (in a clinical setting), female and male urine, and specimens collected in PreservCyt Solution.

The Aptima TV assay 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 TV assay is performed in the laboratory, the target rRNA is isolated from the specimens using 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.

The provided text describes the analytical and clinical studies performed for the Aptima Trichomonas vaginalis Assay. Here's a breakdown of the requested information:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria values for sensitivity, specificity, PPA, or NPA. Instead, it presents the achieved performance. However, implicit acceptance criteria for NAAT assays generally involve high sensitivity and specificity. The reproducibility study tables show numerical targets for agreement (e.g., >95% positivity for LoD, 90.7% to 100% agreement for reproducibility).

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

• Clinical Study 2 (Primary Test Set):
  • Total evaluable specimens: 5502 specimens from 3820 evaluable subjects.
  • Breakdown by specimen type:
    • 1785 patient-collected vaginal swab specimens
    • 1782 female urine specimens
    • 1935 male urine specimens
  • Data Provenance: Prospective, multicenter clinical study conducted at 11 geographically and ethnically diverse US clinical sites (obstetrics and gynecology, family planning, and STI clinics).
  • Retrospective/Prospective: Primarily prospective. Samples were collected from consenting subjects in a prospective study.

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

The document does not mention the use of human experts (e.g., radiologists, pathologists) to establish the ground truth. For this in vitro diagnostic (IVD) device, the ground truth was established by molecular testing.

4. Adjudication Method for the Test Set

The ground truth for the clinical test set was established using a "composite comparator method" or "patient infected status (PIS)" / "composite comparator algorithm (CCA)" based on results from up to three cleared NAATs.

• Method:
  • Specimens were categorized as infected (PIS) or positive (CCA) if a positive result occurred in at least two of the comparator NAATs.
  • Specimens were categorized as not infected or negative if at least 2 of the comparators results were negative.
  • A third (tie-breaker) comparator was only required if the first 2 comparator results were discordant.
  • Specimens that could not be categorized due to missing results from comparator assays were excluded.

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, an MRMC comparative effectiveness study was not applicable and therefore not performed. This is an in vitro diagnostic (IVD) device for the detection of ribosomal RNA from Trichomonas vaginalis. It is a lab-based assay, not an imaging device that requires human readers to interpret results, or AI assistance for human reader improvement.

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

Yes, the performance reported (sensitivity, specificity, PPA, NPA) for the Aptima TV assay is its standalone performance. The assay itself is the "algorithm" in this context; it processes specimens and provides a qualitative result (positive/negative) without direct human interpretation of the assay's raw output for diagnosis. The study evaluates the device's ability to accurately detect the target in various specimens against the established ground truth.

7. The Type of Ground Truth Used

The ground truth used was established using a composite comparator method (sometimes referred to as a "gold standard" or "reference standard" in IVD studies), which relied on the results of multiple (up to three) cleared Nucleic Acid Amplification Tests (NAATs). This is a form of expert consensus among molecular assays.

8. The Sample Size for the Training Set

The document does not explicitly state the sample size for a separate "training set." For IVD assays, particularly those based on well-established molecular biology principles (like NAATs), development and optimization (analogous to "training") often use specific analytical panels or earlier development runs rather than a distinct, large "training set" of clinical samples as seen in machine learning/AI models. The studies described are primarily for validation.

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

Since a distinct "training set" with established ground truth is not explicitly mentioned as a separate phase of the pivotal study, the establishment of ground truth for any developmental or optimization work would likely follow similar principles as the validation ground truth: using reference materials, spiked samples, or well-characterized clinical samples confirmed by established laboratory methods or multiple comparator assays. The document focuses on the validation and reproducibility of the assay.

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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 ATV Assay with the modified TCR, referred to as ATV Assay (Version 2) in this submission is the subject of this premarket notification. The ATV Assay (Version 2) is similar to the ATV Assay originally cleared (ref: K102911), except for the formulation of the TCR. The TCR is a HEPES-buffered solution containing lithium salts and derivatized magnetic beads. A second target capture oligo was added to the TCR formulation in order to accommodate future specimen types.

The TCR modification did not result in the change of assay technology. The ATV Assay (Version 2) uses Target Capture (TC), Transcription Mediated Amplification (TMA), and Hybridization Protection Assay (HPA) technologies to qualitatively detect ribosomal RNA (rRNA) from Trichomonas vaginalis. The overall assay design as well as the assay procedural steps remain unchanged from that previously described in the original 510(k) for the ATV Assay (K102911).

The ATV Assay (Version 2) kit is comprised of 3 boxes:

1. Refrigerated Box Contains the Amplification Reagent, Enzyme Reagent, Probe Reagent and Target Capture Reagent-B
2. Room Temperature Box Contains Amplification Reconstitution Solution, Enzyme Reconstitution Solution, Probe Reconstitution Solution, Selection Reagent and Target Capture Reagent
3. Controls Box Contains the Negative and Positive Controls

The ATV Assay (Version 2) on PANTHER would utilize three specimen collection kits. These collection kits were cleared for use with the originally cleared ATV Assay and other commercialized APTIMA Assays.

1. APTIMA Unisex Swab Specimen Collection Kit for Endocervical and Male Urethral Swab Specimens
2. APTIMA Vaginal Swab Specimen Collection Kit
3. APTIMA Specimen Transfer Kit

Instrumentation
The ATV Assay (Version 2) was validated using the PANTHER System, which was previously cleared in May 2012 (Ref: K111409).

Acceptance Criteria and Device Performance Study for APTIMA® Trichomonas vaginalis Assay (PANTHER® System)

This section provides a summary of the acceptance criteria and the study conducted to demonstrate the APTIMA® Trichomonas vaginalis Assay on the PANTHER® System meets these criteria.

1. Table of Acceptance Criteria and Reported Device Performance

The primary acceptance criteria for this diagnostic device are its clinical sensitivity and specificity across different specimen types and symptom statuses.

Note: The document does not explicitly state numerical acceptance criteria in a structured table. However, the reported performance characteristics (Sensitivity, Specificity, PPV, NPV) with narrow 95% Confidence Intervals consistently demonstrate high agreement with the "patient infected status algorithm," indicating that the device performs as expected for a diagnostic test of this nature, meeting an implicit acceptance threshold for high diagnostic accuracy. The agreement studies with the predicate device further support this.

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

The clinical performance study used the following sample sizes for the test set:

• Vaginal Swabs: 667 (after exclusions for invalid results which were 11 out of 689 initial samples)
• Endocervical Swabs: 700 (after exclusions for invalid results which were 24 out of 737 initial samples)
• PreservCyt Solution liquid Pap specimens: 774 (after exclusions for invalid results which were 1 out of 791 initial samples)

Data Provenance: The study utilized retrospective, leftover specimens collected from consenting subjects during a previous, prospective, multicenter clinical study of the ATV Assay on the TIGRIS DTS System.

• Country of Origin: 9 US clinical sites (obstetrics and gynecology, family planning, and STD clinics).

For the agreement study with the TIGRIS DTS System for asymptomatic subjects:

• Vaginal Swabs: 227
• Endocervical Swabs: 227
• PreservCyt Solution liquid Pap specimens: 226
• Data Provenance: Prospectively collected specimens from asymptomatic subjects enrolled from 6 US clinical sites.

3. Number of Experts Used to Establish Ground Truth and Qualifications

The document does not specify the number of experts or their specific qualifications (e.g., years of experience for radiologists) for establishing the ground truth for the clinical study.

4. Adjudication Method for the Test Set

The ground truth for the clinical performance study was established by a patient infected status algorithm based on the results from two reference tests performed on vaginal swab specimens:

1. Commercially available culture system
2. Wet mount microscopic examination

Adjudication Rule:

• Infected Patient Status: At least one of the reference test results was required to be positive.
• Non-infected Patient Status: Both reference tests were required to be negative.

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

No Multi-Reader Multi-Case (MRMC) comparative effectiveness study was done. This is a diagnostic assay (Nucleic Acid Amplification Test) and its performance is determined by its analytical and clinical characteristics against a defined ground truth, not by human reader interpretation. No human readers are involved in the direct interpretation of the assay results, which are automatically interpreted by the PANTHER System software.

6. Standalone Performance Study (Algorithm Only)

Yes, a standalone performance study (algorithm only, without human-in-the-loop performance) was done. The entire evaluation of the APTIMA® Trichomonas vaginalis Assay on the PANTHER® System, including its analytical and clinical performance, is based on the automated interpretation of the test results by the PANTHER System's software. The assay results (RLU values) are automatically interpreted as negative, positive, or invalid by the system.

7. Type of Ground Truth Used

The type of ground truth used for the clinical studies was an expert consensus-based algorithm derived from established diagnostic methods:

• Culture for Trichomonas vaginalis
• Wet mount microscopic examination

This algorithm defined the "patient infected status" against which the device's performance was measured.

8. Sample Size for the Training Set

The document does not explicitly state the sample size for a "training set" in the context of developing the algorithm itself. The information provided focuses on the validation data set used for clinical performance evaluation. Medical devices, especially diagnostic assays, often undergo development and internal validation on various sample sets, but these are typically not reported as explicitly as training sets in the context of machine learning model development. The focus here is on the analytical and clinical validation of the final assay.

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

As noted above, an explicit "training set" for the algorithm's development is not detailed. The ground truth for validating the assay's performance (the clinical test set) was established using a patient infected status algorithm based on a combination of culture and wet mount microscopic examination results. This is a common practice for validating new diagnostic tests against existing gold standards or established diagnostic pathways.

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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 ATV assay is a nucleic acid amplification test intended for the in vitro qualitative detection of ribosomal RNA from T. vaginalis in patient-collected first catch urine and clinician collected vaginal swabs, endocervical swab and ThinPrep Pap Test specimens collected in Cytyc Preservcyt solution. The assay may be used to test specimens from symptomatic and asymptomatic individuals to aid in the diagnosis of trichomoniasis using the TIGRIS DTS System automated analyzer.

There are 4 kits (1 master and 3 ancillary) that are required to perform the ATV assay on the TIGRIS DTS System. The Master Kit contains 9 reagents and 2 controls and is made up of 3 boxes. Box 1 - the Refrigerated box contains ATV amplification reagent, ATV enzyme reagent, ATV probe reagent and ATV Target Capture reagent-B. Box 2 - the Room Temperature box contains ATV amplification reconstitution solution, ATV enzyme reconstitution reagent, ATV probe reconstitution reagent, ATV selection reagent and ATV target capture reagent. Box 3-the Controls kit box contains ATV positive and negative controls. The three ancillary kits consist of the APTIMA Assay Fluids kit, the APTIMA Auto Detect Reagents kit and APTIMA System Fluids Preservative kit. In addition to the reagents provided in the kit, the assay utilizes four specimen collection kits - the APTIMA unisex swab specimen collection kit for endocervical and male urethral swab specimens, APTIMA vaginal swab specimen collection kit, APTIMA urine specimen collection kit for male and female urine specimens and the APTIMA specimen transfer kit.

Here's an analysis of the provided text to extract the acceptance criteria and study details for the Aptima Trichomonas vaginalis (ATV) assay.

Acceptance Criteria and Device Performance for Aptima Trichomonas vaginalis (ATV) Assay

The Aptima Trichomonas vaginalis (ATV) assay is a qualitative nucleic acid amplification test (NAAT) designed for the detection of ribosomal RNA (rRNA) from T. vaginalis. Its performance was evaluated through various analytical and clinical studies.

1. Acceptance Criteria and Reported Device Performance

The acceptance criteria for the ATV assay are implicitly defined by the reported performance characteristics which are deemed sufficient for reclassification to Class II. The primary performance metrics are related to the accuracy of T. vaginalis detection across different specimen types.

2. Sample Size and Data Provenance for the Test Set (Clinical Study)

• Sample Size: 1025 symptomatic and asymptomatic women were enrolled.
  • Evaluable specimens:
    • Urine: 738 (3 had final invalid results)
    • Vaginal Swabs: 877 (2 had final invalid results)
    • Endocervical Swabs: 922 (2 had final invalid results)
    • PreservCyt solution liquid Pap specimens: 813
• Data Provenance: The study was a "pivotal prospective multicenter clinical trial" conducted with women enrolled from 9 US clinical sites, including obstetric and gynecology, family planning, and STD clinics. This indicates prospective data collection from a diverse US population.

3. Number of Experts and Qualifications for Ground Truth

The document does not explicitly state the number or specific qualifications of individuals who interpreted the predicate tests to establish the ground truth. However, it indicates:

• "2 of the vaginal swab specimens were tested with a commercially available culture system and wet mount microscopic exam to establish infected status."
• This suggests that the ground truth was established by laboratory professionals and/or clinicians skilled in performing and interpreting these traditional diagnostic methods. The document does not specify their level of experience (e.g., radiologist with 10 years of experience).

4. Adjudication Method for the Test Set

The ground truth was established using a "patient infected status algorithm":

• At least one positive reference result (from culture and/or wet mount microscopic exam) established an "infected patient status."
• Both reference tests were required to be negative to establish a "non-infected patient status."

This effectively acts as an adjudication, where discordant results between the two reference methods (culture and wet mount) are resolved by prioritizing a positive finding from either method for "infected" status, and requiring both to be negative for "non-infected" status.

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

No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not performed or described in this document. The study focuses on comparing the assay's performance against traditional diagnostic methods, not on human reader improvement with or without AI assistance.

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

Yes, the study describes the standalone performance of the APTIMA Trichomonas vaginalis Assay. The assay is an in vitro diagnostic device, and its results are automatically interpreted by the TIGRIS DTS System APTIMA Trichomonas vaginalis Software. The reported sensitivity, specificity, PPV, and NPV are characteristics of the automated assay's performance alone, without human interpretation or intervention in the diagnostic call process beyond initial specimen collection and loading.

7. Type of Ground Truth Used

The ground truth used for the clinical study was based on a composite reference standard:

• Expert Consensus (implied by method): "commercially available culture system and wet mount microscopic exam"
• Algorithm-based Patient Infected Status: An algorithm designated a subject as "infected" if at least one of the two reference methods (culture or wet mount) was positive, and "non-infected" if both were negative. This combines established diagnostic methods to form a "gold standard" for the study.

8. Sample Size for the Training Set

The document does not specify a separate training set or its sample size. The description of the clinical trial refers to a "pivotal prospective multicenter clinical trial" where all collected specimens were used for performance evaluation. For in vitro diagnostic assays, developers typically use internal data for assay development and optimization (which can be considered the "training phase"), but this internal data is not usually described in the same detail as the independent clinical validation (the "test set" in AI/ML terminology).

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

Since a specific "training set" is not explicitly mentioned or detailed in the context of this 510(k) submission, the method for establishing its ground truth is also not provided. If an internal "training set" was used during assay development, it would have likely relied on similar established methods (culture, wet mount, or other validated laboratory techniques) to determine the T. vaginalis status of samples for optimizing the assay's parameters.

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