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The Aptima CV/TV assay is an in vitro nucleic acid amplification of RNA from microorganisms associated with vulvovaginal candidiasis and trichomoniasis. The assay utilizes real time transcription-mediated amplification (TMA) to detect and qualitatively report results for the following organisms:

• Candida species group (C. albicans, C. tropicalis, C. parapsilosis, C. dubliniensis)
• Candida glabrata
• Trichomonas vaginalis

The assay differentiates between Candida glabrata and the Candida species group (C spp) by targeting the RNA component of RNAse Pribonucleoprotein; the assay does not differentiate among C spp. For Trichomonas vaginalis, the assay targets ribosomal RNA (rRNA) and differentiates the results for Candida glabrata and C spp. The assay is intended to aid in the diagnosis of vulvovaginal candidiasis and trichomoniasis on the automated Panther system using clinician-collected and patient-collected vaginal swab specimens from females with a clinical presentation consistent with vaginitis or vulvovaginitis.

The Aptima CV/TV assay is an in vitro nucleic acid amplification test for the detection and quantitation of RNA from microorganisms associated with vulvovaginal candidiasis and trichomoniasis in women with a clinical presentation consistent with vaginitis or vulvovaginitis. The Aptima CV/TV assay utilizes the automated Panther system to provide qualitative results to aid in the diagnosis of vulvovaginal candidiasis and trichomoniasis. The assay involves three main steps, all of which take place in a single tube on the Panther system: target capture, target amplification by TMA, and detection of the amplification products (amplicon) by fluorescent labeled probes (torches). The assay incorporates an internal control (IC) in every test to monitor nucleic acid capture, amplification and detection.

Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided text:

Acceptance Criteria and Reported Device Performance

The document doesn't explicitly state "acceptance criteria" for clinical performance in a table format with specific numerical thresholds the device must meet. Instead, it presents the achieved performance metrics (sensitivity, specificity, PPV, NPV) from the clinical study, implying these demonstrated statistics were considered acceptable for clearance. For analytical studies, acceptance is demonstrated by successfully meeting the goals of the study (e.g., all strains detected for inclusivity, no cross-reactivity beyond a certain concentration).

Therefore, for the clinical performance, the reported performance is the demonstration of meeting implied acceptance.

Note: For a medical device, acceptance criteria are typically predefined thresholds in a study protocol that the device performance must surpass. Since these aren't explicitly stated as hard "criteria" with target numbers, I'll present the reported device performance from the clinical study tables.

For Analytical Studies, acceptance was indicated by:

• Analytical Sensitivity (LoD): Predicted detection limits established through probit analysis (Table 6).
• Analytical Inclusivity: All Candida strains and 8/9 T. vaginalis strains detected at 3X LoD, with one T. vaginalis at 4X LoD.
• Cross-Reactivity and Microbial Interference: No cross-reactivity or microbial interference observed for 64 organisms and human cell lines at specified concentrations (Table 7), with minor exceptions noted for Candida famata, Tioconazole, Vaginal Moisturizing Gel, and Glacial Acetic Acid at higher concentrations than the tested limits.
• Within Laboratory Precision: 100% agreement with expected positivity for all positive and negative panel members (Table 9). Signal variability (CV%) for TTime was reported and considered acceptable (Table 10).
• Co-Infection: 100% detection for both targets present in co-infection panels (Table 11), with further testing confirming low C. glabrata and high T. vaginalis detection.
• Reproducibility: 100% agreement with expected results for all panel members across three sites (Table 21). Total %CV values for TTime ranged from 5.64% to 6.77% across organisms/panel members (Table 22), and from 4.29% to 6.89% for controls (Table 23).

Study Details

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

   • Total Subjects Enrolled: 1519 symptomatic women.
   • Evaluable Subjects: 1496.
   • Sample Types: Clinician-collected and patient-collected vaginal swab specimens.
   • Data Provenance:
     • Country of Origin: Geographically diverse US clinical sites (21 sites).
     • Retrospective/Prospective: Prospectively-collected.

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

   • The document does not explicitly state the number of experts used to establish the ground truth.
   • Qualifications of Experts: Not specified. The reference methods are described (Candida culture, PCR/bi-directional sequencing, FDA-cleared molecular TV assay, FDA-cleared culture-based TV test), but the individuals interpreting these results to form the ground truth are not detailed.

3. Adjudication Method for the Test Set:

   • The document describes how the reference results for Candida and T. vaginalis were established:
     • Candida species group and C. glabrata: Based on a combination of Candida growth in culture, as well as PCR/bi-directional sequencing of both Aptima swab samples (leftover after testing) for subjects with positive Candida culture results.
     • T. vaginalis: A patient infected status (PIS) determined for each subject based on results from an FDA-cleared molecular TV assay and an FDA-cleared culture-based TV test.
   • This indicates a composite reference standard approach (multiple tests combined) rather than a simple 2+1 or 3+1 expert adjudication for diagnostic imaging, which is not applicable here.

4. 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 done. This refers to a medical device for in vitro diagnostic testing (nucleic acid amplification test) rather than an AI-assisted diagnostic imaging device/software the question implies. The study evaluates the performance of the assay itself against established reference methods.

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

   • Yes, this was a standalone performance study. The Aptima CV/TV assay is an in vitro diagnostic test performed on an automated Panther system. Its performance (sensitivity, specificity) is evaluated directly against reference methods without human interpretation of the assay's output as an "assistance" to a physician. The "Panther system software uses an Aptima CV/TV assay-specific algorithm that interprets the amplification signal emergence times to generate a Positive or Negative status for each target organism in the sample." This is a completely automated interpretation by the device.

6. The Type of Ground Truth Used:

   • Composite Reference Standard / Expert Consensus (implied by combining tests):
     • For Candida species group and C. glabrata: Ground truth was established by combining Candida growth in culture and PCR/bi-directional sequencing.
     • For T. vaginalis: Ground truth (Patient Infected Status - PIS) was established using an FDA-cleared molecular TV assay and an FDA-cleared culture-based TV test.

7. The Sample Size for the Training Set:

   • The document does not provide information on a separate training set or its sample size. This is common for IVD assays where "training" refers more to assay development and optimization rather than machine learning model training on a specific clinical dataset. The clinical performance study described serves as the validation dataset.

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

   • Since no separate training set is detailed, information on how its ground truth was established is not provided. The ground truth for the clinical validation described above was established using composite reference standards, as per point 6.

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