(80 days)
The APTIMA Assay for Chlamydia trachomatis is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection of ribosomal RNA (rRNA) from Chlamydia trachomatis (CT) in clinician-collected endocervical, vaginal and male urethral swab specimens, patient-collected vaginal swab specimens*, and female and male urine specimens. The assay may be used to test specimens from symptomatic and asymptomatic individuals to aid in the diagnosis of chlamydial urogenital disease.
*Patient-collected vaginal swab specimens are an option for screening women when a pelvic exam is not otherwise indicated. The vaginal swab specimen collection kit is not for home use.
The APTIMA Assay for Chlamydia trachomatis is a target amplification nucleic acid probe test that utilizes target capture for the in vitro qualitative detection of rRNA from Chlamydia trachomatis in clinician-collected endocervical, vaginal and male urethral swab specimens, patient-collected vaginal swab specimens, and female and male urine specimens. The APTIMA Assay for Chlamydia trachomatis (APTIMA CT Assay) may be used to test specimens from symptomatic and asymptomatic individuals to aid in the diagnosis of chlamydial urogenital disease.
Acceptance Criteria and Device Performance for GEN-PROBE® APTIMA® Assay for Chlamydia trachomatis
Due to the nature of the provided document, which is a 510(k) summary for a diagnostic test, much of the detailed information regarding study design, sample sizes, and ground truth establishment (especially for training sets) is not explicitly present in the provided text. The document focuses on demonstrating substantial equivalence to predicate devices and detailing the intended use and performance characteristics.
1. Table of Acceptance Criteria and Reported Device Performance
The provided document does not explicitly state pre-defined acceptance criteria in a quantitative manner as typically seen for AI/ML validation. Instead, it compares the performance of the APTIMA CT Assay with cell culture, highlighting the superior sensitivity of NAATs. The focus is on demonstrating similar or improved performance compared to predicate devices or the "gold standard" of the time (cell culture).
The key performance characteristics highlighted are:
| Acceptance Criteria (Implied) | Reported Device Performance (APTIMA CT Assay) |
|---|---|
| Higher clinical sensitivity than cell culture | Demonstrated higher clinical sensitivity than cell culture. (Buimer et al., 1996; Crothfelt et al., 1998; Jaschek et al., 1993; Stary et al., 1998) - Note: These are references to general NAAT performance, not specific APTIMA CT Assay data within this document. |
| Comparable performance to predicate NAATs | Implied through substantial equivalence to GEN-PROBE® APTIMA® Combo 2 Assay and Becton Dickenson ProbeTec™ ET System CT and CT/GC Assays. |
| Reduced issues of specimen inhibition compared to first-generation NAATs | Demonstrated benefits of target capture, TMA, and HPA in reducing specimen inhibition. (Chong et al., 2003; Gaydos et al, 2003) |
| In vitro qualitative detection of rRNA from Chlamydia trachomatis in various specimen types | Successfully detects rRNA from CT in clinician-collected endocervical, vaginal and male urethral swab specimens, patient-collected vaginal swab specimens, and female and male urine specimens. |
2. Sample Size Used for the Test Set and Data Provenance
The provided document does not explicitly state the specific sample sizes used for the test set. It references several external studies (e.g., Buimer et al., Crothfelt et al., Jaschek et al., Stary et al., Chong et al., Gaydos et al.) to support claims about NAAT performance and the benefits of the APTIMA CT Assay's technology. However, the exact sample sizes and the specific data used for the regulatory submission are not detailed within this text.
Data Provenance: The document does not specify the country of origin of the data referenced in the studies. The studies are described as comparing NAATs to cell culture or discussing technological advancements. The document indicates that "an estimated 783,242 new cases of C. trachomatis infections were reported in 2001 in the United States alone," suggesting a focus on the U.S. context, but this does not directly specify the origin of the clinical study data.
Retrospective or Prospective: The document does not explicitly state whether the studies referenced were retrospective or prospective.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not provide details on the number or qualifications of experts used to establish ground truth for the test set. For C. trachomatis diagnostics, particularly in the context of comparisons to cell culture, the "ground truth" would typically be established by highly qualified clinical laboratory personnel adhering to established protocols for the reference method (e.g., cell culture).
4. Adjudication Method for the Test Set
The document does not explicitly state an adjudication method for the test set. Given that the "ground truth" for comparing diagnostic tests like this often relies on a reference method (like cell culture) rather than subjective expert interpretation, a complex adjudication process like 2+1 or 3+1 might not be applicable in the same way as it would for image-based diagnostic AI. Discrepancy resolution for discordant results between the new assay and the reference method would be the more relevant process, but this is not detailed.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study Was Done
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. MRMC studies are typically performed for devices that involve human readers interpreting output (e.g., medical images). The APTIMA CT Assay is an in vitro diagnostic test that provides a qualitative (positive/negative) result without human interpretation of complex patterns, thus an MRMC study is not relevant.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
The APTIMA CT Assay is a standalone algorithm/device. It is an automated in vitro diagnostic test that provides a direct result from a clinical specimen without real-time human intervention in the interpretation of the core assay output. The performance described (e.g., sensitivity, specificity relative to cell culture) intrinsically represents its standalone performance.
7. The Type of Ground Truth Used
The primary type of ground truth used as a comparator for the performance assessment of NAATs (and by extension for the APTIMA CT Assay's claims) was cell culture. The document states: "Cell culture was once considered to be the 'gold standard' for detection of C. trachomatis." However, it then goes on to state that NAATs have demonstrated higher clinical sensitivity than culture, implying a shift in the perceived "gold standard" or at least a recognition of NAATs' superior performance.
8. The Sample Size for the Training Set
The document does not provide information regarding the sample size for a training set. This is typical for a traditional IVD. Unlike AI/ML devices that explicitly use "training data" to develop algorithms, traditional diagnostic assays are developed and optimized through laboratory research and verification studies, rather than machine learning on a predefined "training set."
9. How the Ground Truth for the Training Set Was Established
Similarly to point 8, the concept of a "training set" with a defined "ground truth" in the AI/ML sense is not applicable to this traditional in vitro diagnostic device. The ground truth for developing and verifying such an assay would involve known positive and negative samples, characterized through established laboratory methods, including potentially thoroughly characterized clinical specimens or spiked samples with known concentrations of the pathogen. These would be used for assay optimization, specificity testing, and analytical sensitivity studies during development.
§ 866.3120 Chlamydia serological reagents.
(a)
Identification. Chlamydia serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to chlamydia in serum. Additionally, some of these reagents consist of chlamydia antisera conjugated with a fluorescent dye used to identify chlamydia directly from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of disease caused by bacteria belonging to the genusChlamydia and provides epidemiological information on these diseases. Chlamydia are the causative agents of psittacosis (a form of pneumonia), lymphogranuloma venereum (a venereal disease), and trachoma (a chronic disease of the eye and eyelid).(b)
Classification. Class I (general controls).