(141 days)
The Thermo BioStar® GC OIA assay is an Optical ImmunoAssay test for the rapid qualitative detection of gonococcal antigen (L7/L12 ribosomal protein) in female endocervical swab and male urine specimens. Urine specimens must be prepared using an accessory Urine Filtration Device (UFD) for concentration and extraction. This test is intended for in vitro diagnostic use as an aid in identifying the presence of Neisseria gonorrhoeae antigen. The assay is intended for use with symptomatic females and males, in populations at risk for sexually transmitted diseases.
The GC OIA test involves the qualitative extraction and detection of an antigen unique to N. gonorrhoeae. The Optical ImmunoAssay technology enables the direct visual detection of a physical change in the optical thickness of molecular thin films. This change is a result of antigen-antibody binding on an optical surface (silicon wafer). When an extracted specimen is placed directly on the optical surface, the immobilized specific antibodies capture the antibody-enzyme conjugate is then added for form an immune complex "sandwich" of immobilized antibody-sample-antibody HRP on the surface. After washing, the substrate is added, increasing the thickness (mass enhancement) of the molecular thin film. This change in thickness alters the reflected light path and is visually perceived as a color change. Slight changes in optical thickness produce a distinct, visible color change. A positive result appears as a purple spot on the predominant gold background. When antigen is not present in the specimen, no binding takes place. Therefore, the optical thickness remains unchanged and the surface retains the original gold color indicating a negative result.
Here's a summary of the acceptance criteria and study details for the GC OIA® device, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
| Metric | Acceptance Criteria (Implied) | Reported Device Performance (Female Endocervical Swabs) | Reported Device Performance (Male Urine) |
|---|---|---|---|
| Sensitivity | Not explicitly stated | 70.7% | 93.2% |
| Specificity | Not explicitly stated | 99.4% | 97.5% |
| Reproducibility (Urine) | Not explicitly stated | Not applicable | 98.1% (95% CI = 93.8-99.3) |
| Reproducibility (Swab) | Not explicitly stated | 88.9% (95% CI = 93.8-99.3) | Not applicable |
| PPV (Positive Predictive Value) | Not explicitly stated | 90.6% | 94.0% |
| NPV (Negative Predictive Value) | Not explicitly stated | 97.5% | 97.2% |
Note: The document does not explicitly state numerical acceptance criteria for sensitivity, specificity, or reproducibility. The reported performance is presented as the outcome of the clinical study, implying these values were deemed acceptable for substantial equivalence.
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: A total of 904 valid results were obtained from symptomatic patient specimens.
- Data Provenance: The study was a "multicenter study" conducted at "four geographically diverse clinical sites." The data is prospective as it was collected from "symptomatic patient specimens" for the purpose of the study.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications of Those Experts
This information is not provided in the given text. It mentions a "commercial culture media, with secondary confirmation testing by LCR (Ligase Chain Reaction)" as the comparison method for establishing ground truth, but does not detail the involvement or qualifications of human experts in this process.
4. Adjudication Method for the Test Set
This information is not provided in the given text. The ground truth was established by "commercial culture media, with secondary confirmation testing by LCR," but the specific adjudication method if there were discrepancies between these methods or if human experts were involved in adjudication is not described.
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. The study compared the device with a "historical reference method" (Neisseria gonorrhoeae culture) and used secondary confirmation by LCR, not human readers with and without AI assistance.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done
Yes, a standalone study was done. The performance data (sensitivity, specificity, etc.) are reported for the GC OIA® assay itself, functioning without human interpretation affecting the result. The device is described as enabling "direct visual detection of a physical change...visually perceived as a color change," where a "positive result appears as a purple spot." This implies the human component is simply observing the color change, not interpreting complex images or performing diagnostic reasoning.
7. The Type of Ground Truth Used
The ground truth used was a combination of:
- Culture: "Commercial culture media" was the primary comparison method.
- Molecular Confirmation: "Secondary confirmation testing by LCR (Ligase Chain Reaction)" was used. This indicates a robust ground truth standard, likely aiming to resolve ambiguous culture results or provide higher certainty.
8. The Sample Size for the Training Set
The sample size for the training set is not explicitly stated in the provided text. The document describes clinical studies that established "performance characteristics," implying these involved a test set. There's no separate mention of a distinct training set.
9. How the Ground Truth for the Training Set Was Established
Since a separate training set is not explicitly mentioned, the method for establishing its ground truth is also not provided. If the reported clinical study data involved an internal training phase, the ground truth would presumably have been established similarly to the test set (culture with LCR confirmation).
§ 866.3390
Neisseria spp. direct serological test reagents.(a)
Identification. Neisseria spp. direct serological test reagents are devices that consist of antigens and antisera used in serological tests to identifyNeisseria spp. from cultured isolates. Additionally, some of these reagents consist ofNeisseria spp. antisera conjugated with a fluorescent dye (immunofluorescent reagents) which may be used to detect the presence ofNeisseria spp. directly from clinical specimens. The identification aids in the diagnosis of disease caused by bacteria belonging to the genusNeisseria, such as epidemic cerebrospinal meningitis, meningococcal disease, and gonorrhea, and also provides epidemiological information on diseases caused by these microorganisms. The device does not include products for the detection of gonorrhea in humans by indirect methods, such as detection of antibodies or of oxidase produced by gonococcal organisms.(b)
Classification. Class II (performance standards).