(180 days)
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:
- Refrigerated Box Contains the Amplification Reagent, Enzyme Reagent, Probe Reagent and Target Capture Reagent-B
- Room Temperature Box Contains Amplification Reconstitution Solution, Enzyme Reconstitution Solution, Probe Reconstitution Solution, Selection Reagent and Target Capture Reagent
- 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.
- APTIMA Unisex Swab Specimen Collection Kit for Endocervical and Male Urethral Swab Specimens
- APTIMA Vaginal Swab Specimen Collection Kit
- 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.
| Performance Metric | Specimen Type | Symptom Status | Acceptance Criteria (Implicit from prior clearance/predicate, demonstrated as 95% Confidence Interval) | Reported Device Performance (95% CI) |
|---|---|---|---|---|
| Sensitivity | Clinician-collected Vaginal Swab (CVS) | Asymptomatic | Expected to be high (e.g., >80% or 90%) | 100% (75.8-100) |
| Symptomatic | Expected to be high | 100% (93.7-100) | ||
| Overall | Expected to be high | 100% (94.7-100) | ||
| Endocervical Swab (ES) | Asymptomatic | Expected to be high | 100% (80.6-100) | |
| Symptomatic | Expected to be high | 100% (93.0-100) | ||
| Overall | Expected to be high | 100% (94.6-100) | ||
| PreservCyt Solution liquid Pap (PCyt) | Asymptomatic | Expected to be high | 100% (83.2-100) | |
| Symptomatic | Expected to be high | 100% (94.3-100) | ||
| Overall | Expected to be high | 100% (95.6-100) | ||
| Specificity | Clinician-collected Vaginal Swab (CVS) | Asymptomatic | Expected to be high (e.g., >95%) | 97.3% (94.6-98.7) |
| Symptomatic | Expected to be high | 98.8% (97.0-99.5) | ||
| Overall | Expected to be high | 98.2% (96.7-99.0) | ||
| Endocervical Swab (ES) | Asymptomatic | Expected to be high | 98.3% (96.1-99.3) | |
| Symptomatic | Expected to be high | 97.9% (95.8-99.0) | ||
| Overall | Expected to be high | 98.1% (96.7-98.9) | ||
| PreservCyt Solution liquid Pap (PCyt) | Asymptomatic | Expected to be high | 99.4% (97.7-99.8) | |
| Symptomatic | Expected to be high | 97.9% (95.9-98.9) | ||
| Overall | Expected to be high | 98.6% (97.4-99.2) |
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:
- Commercially available culture system
- 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.
§ 866.3860
Trichomonas vaginalis nucleic acid assay.(a)
Identification. ATrichomonas vaginalis nucleic acid assay is a device that consists of primers, probes, enzymes, and controls for the amplification and detection of trichomonas nucleic acids in endocervical swabs, vaginal swabs, and female urine specimens, from women symptomatic for vaginitis, cervicitis, or urethritis and/or to aid in the diagnosis of trichomoniasis in asymptomatic women. The detection of trichomonas nucleic acids, in conjunction with other laboratory tests, aids in the clinical laboratory diagnosis of trichomoniasis caused byTrichomonas vaginalis .(b)
Classification. Class II (special controls). The special controls are set forth in FDA's guideline document entitled: “Class II Special Controls Guideline: Nucleic Acid Amplification Assays for the Detection ofTrichomonas vaginalis; Guideline for Industry and Food and Drug Administration Staff.” See § 866.1(e) for information on obtaining this document.