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510(k) Data Aggregation
(153 days)
cobas CTNG for use on cobas 6800/8800 systems
The cobas® CT/NG for use on the cobas® 6800/8800 Systems 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) and/or Neisseria gonorrhoeae (NG) DNA in male and female urine, clinician-instructed self-collected vaginal swab specimens (collected in a clinical setting), and clinician-collected vaginal swab specimens, endocervical swab specimens, oropharyngeal (throat) swab specimens and anorectal swab specimens all collected in cobas® PCR Media (Roche Molecular Systems, Inc.), and cervical specimens collected in PreservCyt® Solution. This test is intended as an aid in the diagnosis of chlamydial and gonococcal disease in both symptomatic and asymptomatic individuals.
The cobas® CT/NG for use on the cobas® 6800/8800 systems 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) and/or Neisseria gonorrhoeae (NG) DNA. The current submission is a device modification for the claim extension to include oropharyngeal (throat) and anorectal swab specimens to cleared clinical specimen types. The assay’s principle relies on polymerase chain reaction (PCR) for amplification and a paired reporter and quencher fluorescence-labeled probes (TaqMan Technology) using fluorescence resonance energy transfer (FRET) for detection. Results are analyzed based on PCR cycle threshold analysis.
Here's a summary of the acceptance criteria and study details for the cobas CT/NG device, extracted from the provided FDA 510(k) clearance letter:
1. Table of Acceptance Criteria (Implicit) and Reported Device Performance
The document doesn't explicitly state "acceptance criteria" as a separate table, but the clinical performance results serve as the evidence to meet the implied criteria for sensitivity and specificity in the new specimen types.
| Metric | Target (Implicit Acceptance Criteria) | Reported Device Performance (CT - Anorectal) | Reported Device Performance (CT - Oropharyngeal) | Reported Device Performance (NG - Anorectal) | Reported Device Performance (NG - Oropharyngeal) |
|---|---|---|---|---|---|
| Sensitivity | High (e.g., typically >90% for diagnostic tests) | 95.1% (90.2%, 97.6%) | 100.0% (87.9%, 100.0%) | 99.0% (94.6%, 99.8%) | 100.0% (96.2%, 100.0%) |
| Specificity | High (e.g., typically >95-99% for diagnostic tests) | 99.2% (98.8%, 99.5%) | 99.8% (99.6%, 99.9%) | 99.3% (98.9%, 99.6%) | 98.9% (98.4%, 99.2%) |
Note: The confidence intervals (CIs) are provided as ranges for the reported performance.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set:
- Subjects Enrolled: 2,390 (2,439 subjects were consented, but 49 excluded).
- Anorectal Specimens Tested: 2,365
- Oropharyngeal Specimens Tested: 2,382
- Total Samples: 4,747 (2,365 anorectal + 2,382 oropharyngeal)
- Data Provenance: Multi-site, prospective collection study from 8 geographically diverse clinic sites (STD, HIV, Family Planning, and STD Research). The country of origin is not explicitly stated but is implied to be the US given the FDA clearance.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The ground truth was established by a composite reference method using three commercially available CT/NG NAATs. There's no mention of human experts defining the ground truth for individual cases.
4. Adjudication Method for the Test Set
The adjudication method used for establishing the "Infection Status (IS)" (ground truth) was a 2-out-of-3 concordance rule involving three comparator NAAT assays:
- A positive IS was derived when at least 2 of the 3 comparator reference assays were positive.
- If one of the comparator assays was Uninterpretable/Invalid/Failed, the two remaining assays had to be concordant to define the IS as Positive (+) or Negative (-).
- Any other combination of Uninterpretable/Invalid/Failed and valid results were excluded from the analyses.
5. If a Multi Reader Multi Case (MRMC) Comparative Effectiveness Study was Done
No, an MRMC comparative effectiveness study was not conducted. This study focused on the standalone performance of the cobas CT/NG system against a composite reference standard, not on comparing human reader performance with and without AI assistance.
6. If a Standalone Study Was Done
Yes, a standalone study was done. The clinical performance evaluation directly tested the cobas CT/NG system against the established Infection Status (ground truth) for each specimen type. The results are presented as the device's sensitivity and specificity.
7. The Type of Ground Truth Used
The ground truth used was an expert consensus of commercially available NAATs, forming a "Infection Status (IS)" algorithm. It is a composite reference standard.
8. The Sample Size for the Training Set
The document does not provide information on the sample size used for the training set. The 510(k) pertains to a "device change" (claim extension) for an already cleared device (K173887). The training would have occurred during the development of the original cleared device. This submission focuses on the validation for new specimen types.
9. How the Ground Truth for the Training Set Was Established
The document does not provide information on how the ground truth for the training set was established. Similar to the training set size, this information would likely be part of the original K173887 submission for the device development. This current submission focuses on evaluating the device's performance for expanded claims.
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