(891 days)
IMx SELECT Chlamydia is a Micropaticle Enzyme Immunoassay (MEIA) for the qualitative detection of chlamydial LPS antigen and is indicated for use in testing female endocervical swab specimens, and male urethral swab specimens from symptomatic individuals to identify Chlamvia trachomatis. The IMx SELECT Chamydia Blocking Reagent may be used to verify the chlamydial specificity of the antigen detected.
Micropaticle Enzyme Immunoassay (MEIA) for the qualitative detection of chlamydial LPS antigen.
The provided text describes the IMx SELECT Chlamydia diagnostic device and its performance compared to cell culture for detecting Chlamydia trachomatis.
Here's an analysis of the acceptance criteria and the study proving the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria (e.g., "The device must achieve a sensitivity of at least X%"). Instead, it presents the device's performance in terms of relative sensitivity and specificity against C. trachomatis cell culture as the reference method, with a focus on demonstrating "substantial equivalence."
However, we can infer the reported performance metrics from the study results. The primary comparison is between the IMx SELECT Chlamydia assay and isolation of C. trachomatis in tissue culture.
| Acceptance Criteria (Implied / Comparator Performance) | Reported Device Performance (IMx SELECT Chlamydia) |
|---|---|
| Relative Sensitivity (vs. Cell Culture with Discordant Resolution by DFA) | 84.1% (230/261) (95% CI: 63.6-91.4) for Symptomatic Male |
| 89.9% (148/164) (95% CI: 83.4-94.8) for Female Total | |
| 86.1% (230/261) (95% CI: 83.6-91.9) for Grand Total | |
| Relative Specificity (vs. Cell Culture with Discordant Resolution by DFA) | 98.5% (982/997) (95% CI: 97.7-99.3) for Female Total |
| 99.0% (356/360) (95% CI: 97.4-99.7) for Symptomatic Male | |
| 98.7% (1366/1383) (95% CI: 98.0-99.2) for Grand Total | |
| Positive Predictive Value | (Not clearly stated as an acceptance criterion, but reported) |
| Negative Predictive Value | (Not clearly stated as an acceptance criterion, but reported) |
Important Note: The confidence intervals for sensitivity, particularly for "Symptomatic Male" (63.6-91.4%) and "FEMALE: Other" (83.6-98.8%), are quite wide, suggesting variability or smaller subgroups. The "Grand Total" provides a more robust overall statistical picture.
2. Sample size used for the test set and the data provenance
- Sample Size: A total of 1647 specimens were used for the test set.
- Data Provenance: The specimens were obtained from patients attending 6 different clinics, including sexually transmitted disease clinics, family planning clinics, and OB/GYN clinics. The study appears to be prospective as it involves collecting specimens from patients at the clinics for testing. The country of origin is not explicitly stated, but given "Abbott Park, Ill." as the submitter's address, it is likely the United States.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
The document does not specify the number of experts or their qualifications for establishing the ground truth.
4. Adjudication method for the test set
The ground truth was established by comparing the IMx SELECT Chlamydia assay to isolation of C. trachomatis in tissue culture. For discordant results (where the IMx SELECT Chlamydia result differed from the initial cell culture result), a DFA (Direct Fluorescent Antibody) test was used for resolution. This indicates a form of 2+1 adjudication where the initial two methods (IMx SELECT Chlamydia and Cell Culture) are compared, and a third method (DFA) is used to resolve discrepancies.
5. 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 study evaluates a diagnostic assay, not an AI-assisted human reader interpretation. Therefore, there is no information on how human readers improve with AI assistance.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- Yes, a standalone performance evaluation was done. The IMx SELECT Chlamydia device itself is an automated immunoassay. Its performance metrics (relative sensitivity, relative specificity) are reported for the device operating independently without human interpretation influencing the test result beyond standard laboratory procedures (e.g., sample handling, loading).
7. The type of ground truth used
The primary ground truth used was isolation of C. trachomatis in tissue culture, with Discordant Resolution by DFA for any discrepancies between the test device and the culture. This is a common and accepted reference standard for Chlamydia trachomatis detection.
8. The sample size for the training set
The document does not provide information on a specific training set or its sample size. This is a diagnostic assay (MEIA), which typically relies on established biochemical reactions rather than machine learning models that require explicit training sets. The development and validation of such assays involve different processes than those for AI algorithms.
9. How the ground truth for the training set was established
As there is no explicit training set mentioned for an AI/machine learning model, this question is not applicable in the context of this traditional diagnostic assay. The "ground truth" establishment for the assay development would have involved optimizing reagents and protocols to accurately detect C. trachomatis antigen through rigorous laboratory testing using well-characterized samples.
§ 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).