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K Number
K973707
Device Name
ROCHE AMPLICOR CT/NG TEST FOR CHLAMYDIA TRACHOMATIS
Manufacturer
ROCHE MOLECULAR SYSTEMS, INC.
Date Cleared
1999-08-04

(674 days)

Product Code
MKZ
Regulation Number
866.3120
Type
Traditional
Panel
MI
Reference & Predicate Devices
N/A
AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

The AMPLICOR CT/NG Test for Chlamydia trachomatis is a qualitative in vitro test for the detection of Chlamydia trachomatis plasmid DNA in urine from males and females, in endocervical swab specimens from symptomatic or asymptomatic females, and in urethral swab specimens as evidence of symptomatic or asymptomatic infection with Chlamydia trachomatis. Chlamydia trachomatis DNA is detected by Polymerase Chain Reaction (PCR) amplification of target DNA and by hybridization capture of amplified target and by hybridization capture of the amplified target.

Device Description

The AMPLICOR CT/NG Test for Chlamydia trachomatis is a multiplex in vitro diagnostic test for the detection of Chlamydia trachomatis in male and female urogenital specimens. The AMPLICOR CT/NG Test for Chlamydia trachomatis also has an Internal Control that identifies specimens that contain substances inhibitory to PCR.

AI/ML Overview

The AMPLICOR™ CT/NG Test for Chlamydia trachomatis is a qualitative in vitro test designed to detect Chlamydia trachomatis plasmid DNA in urine (from males and females), endocervical swab specimens (from symptomatic or asymptomatic females), and urethral swab specimens (as evidence of symptomatic or asymptomatic infection). The device utilizes Polymerase Chain Reaction (PCR) amplification and hybridization capture of the amplified target DNA.

Acceptance Criteria and Device Performance

The provided document does not explicitly state pre-defined acceptance criteria (e.g., minimum sensitivity or specificity targets). Instead, it presents the results of clinical performance evaluations against a composite reference standard (culture and DFA). The reported performance metrics are:

MetricValue (with 95% CI)
CLINICAL PERFORMANCE (Female, combined swab and urine)
SensitivityAsymptomatic: 93.1% (88.8-98.4) Symptomatic: 94.3% (89.9-98.7)
SpecificityAsymptomatic: 98.0% (97.1-98.8) Symptomatic: 97.7% (96.7-98.6)
CLINICAL PERFORMANCE (Male, combined swab and urine)
SensitivityAsymptomatic: 92.9% (90.7-95.1) Symptomatic: 92.4% (90.1-94.6) (from total for males, Table 3)
SpecificityAsymptomatic: 94.7% (93.9-95.5) Symptomatic: 94.8% (94.1-95.6) (from total for males, Table 3)
NON-CLINICAL PERFORMANCE
Analytical Sensitivity (Limit of Detection)1 Inclusion Forming Unit (IFU) per test for all 15 Chlamydia serovars
Analytical SpecificityNegative results for 132 bacteria, 6 fungi, 1 protozoon, and 11 virus isolates at ≥ 10^4 copies of genomic DNA per test
Precision (% Correct Results)100% for CTM (0, 1.25, 3.75, 6.25 IFU/test) and Urine (0, 1, 3, 5 IFU/test) specimens

Study Details

  1. Sample sizes used for the test set and data provenance:

    • Total specimens collected: 8521 from 4298 patients.
    • Specimens included in analysis: 8309 (with Internal Control results used) or 8378 (with Internal Control results not used) after excluding equivocal (143) and repeatedly inhibitory (69) specimens.
    • Data Provenance:
      • Country of origin: Not explicitly stated, though the study was conducted at "six geographically diverse sites." The submission to the FDA is from a US company.
      • Retrospective or Prospective: The clinical study appears to be prospective, as specimens were "obtained from all patients entered into the study," and specific inclusion criteria (e.g., patient not on antibiotics, valid culture result, met storage requirements) were applied.

  2. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

    • The ground truth for the clinical study was established by standard culture with cyclohexamide treated McCoy cells stained with fluorescein-labeled monoclonal antibody for C. trachomatis, and for culture-negative swab specimens, DFA (Direct Fluorescent Antibody) for the presence of C. trachomatis.
    • The document does not specify the number of experts or their qualifications for performing these reference methods. These are laboratory-based diagnostic tests, typically performed by trained medical technologists or microbiologists.

  3. Adjudication method for the test set:

    • The primary reference standard was a composite of culture and DFA.
    • When the AMPLICOR test results were positive but the composite culture/DFA was negative ("false positive"), alternate PCR testing using oligonucleotide primers targeted for a region of the C. trachomatis MOMP gene was performed. However, the MOMP test results "were not used to calculate the clinical performance characteristics of the test and are reported for information purposes only." This suggests the MOMP assay served as a secondary, confirmatory test for discordant results, but not as part of the primary ground truth adjudication for calculating sensitivity and specificity. There is no mention of a formal expert adjudication panel.

  4. If a multi-reader multi-case (MRMC) comparative effectiveness study was done:

    • No, an MRMC comparative effectiveness study was not done. This device is an in vitro diagnostic test, not an AI system interpreted by human readers. Therefore, the concept of human readers improving with or without AI assistance is not applicable.

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

    • Yes, the data presented reflects the standalone performance of the AMPLICOR CT/NG Test for Chlamydia trachomatis as an in vitro diagnostic device. There is no human-in-the-loop element described for making the diagnostic determination.

  6. The type of ground truth used:

    • The ground truth used was a composite reference standard consisting of:
      • Standard cell culture followed by immunofluorescent staining for C. trachomatis.
      • Direct Fluorescent Antibody (DFA) for C. trachomatis on culture-negative swab specimens.
    • Additionally, an alternate PCR (MOMP gene target) was used for investigational purposes to understand discordant results (AMPLICOR positive, culture/DFA negative), suggesting a form of expanded gold standard or latent class analysis was considered, though not formally incorporated into the primary performance calculations.

  7. The sample size for the training set:

    • The document does not describe a "training set" in the context of an algorithm or machine learning model. This is a traditional in vitro diagnostic device. The concept of training data is not applicable here. The non-clinical performance studies (analytical sensitivity, specificity, precision) were performed on laboratory-prepared samples.

  8. How the ground truth for the training set was established:

    • As there is no training set for an algorithm described, this question is not applicable. The non-clinical performance studies used known quantities of C. trachomatis IFU (Inclusion Forming Units) or other microbial isolates as their "ground truth" to determine analytical characteristics.

§ 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).