(121 days)
Toxogen is an in vitro diagnostic, rapid latex particle agglutination test for the qualitative and semiquantitative determination of total anti-toxoplasma antibodies in human serum. The test may be used with a single specimen to estimate the immunologic response of the individual or with paired acute and convalescent sera as an aid in the diagnosis of primary, acute or reactivated toxoplasmosis. This assay is not FDA cleared for use in blood or plasma donor screening.
Toxogen is an in vitro diagnostic, rapid latex particle agglutination test for the qualitative and semiquantitative determination of total anti-toxoplasma antibodies in human serum. The new Toxogen is a modified version of the predicate Toxogen with a larger latex particle size to increase sensitivity from 10 IU/mL to 5 IU/mL.
The provided text describes the Toxogen device, an in vitro diagnostic test for Toxoplasma gondii antibodies. Here's a breakdown of the acceptance criteria and study details:
1. Acceptance Criteria and Reported Device Performance
The acceptance criteria are implied by the comparison to a predicate device, focusing on maintaining or improving sensitivity and overall agreement.
| Acceptance Criteria Category | Specific Metric | Reported Device Performance |
|---|---|---|
| Sensitivity | Improve or maintain sensitivity compared to predicate (target: 10 IU/mL to 5 IU/mL) | Relative sensitivity of 100% (compared to predicate Toxogen for qualitative method) |
| Specificity | Maintain specificity compared to predicate | Relative specificity of 91% (compared to predicate Toxogen for qualitative method) |
| Reproducibility | 100% agreement within one 2-fold dilution for semiquantitative results | 100% reproducibility (for semi-quantitative procedure) |
| Substantial Equivalence | Performance, intended use, safety, and effectiveness | Found substantially equivalent to predicate device |
2. Sample Size and Data Provenance
- Test Set Sample Size: 100 serum samples were used for the method comparison study (qualitative method). 9 serum samples (3 negative, 3 weak positive, 3 high positive) were used for the reproducibility study.
- Data Provenance: Not explicitly stated (e.g., country of origin, retrospective/prospective).
3. Number of Experts and Qualifications for Ground Truth
- Experts for Ground Truth: Not applicable or not specified. Ground truth appears to be based on comparison to a predicate device's results.
- Qualifications of Experts: Not applicable, as expert involvement in establishing a gold standard is not mentioned.
4. Adjudication Method
- Adjudication method: Not applicable. The study compares the new device's results directly against the predicate device's results, not an independent expert adjudication process.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- MRMC Study: No, there is no mention of a Multi-Reader Multi-Case (MRMC) comparative effectiveness study, nor any evaluation of human readers with or without AI assistance. This device is an in-vitro diagnostic test kit, not an AI or imaging device that would typically involve human reader studies.
6. Standalone Performance Study
- Standalone Performance: Yes, the device's performance was evaluated in terms of its qualitative sensitivity and specificity against a predicate device, and its reproducibility. This is an evaluation of the algorithm/device's standalone performance.
7. Type of Ground Truth Used
- Ground Truth Type: For the qualitative method comparison, the "ground truth" was established by the predicate Toxogen device's results. For the reproducibility study, the results were compared to each other across different operators and days to assess consistency.
8. Sample Size for the Training Set
- Training Set Sample Size: Not applicable. The document describes a performance study for a diagnostic test kit, not a machine learning model, so there is no concept of a "training set" in this context.
9. How Ground Truth for the Training Set was Established
- Ground Truth for Training Set: Not applicable, as there is no training set for this type of device.
§ 866.3780
Toxoplasma gondii serological reagents.(a)
Identification. Toxoplasma gondii serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies toToxoplasma gondii in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identifyToxoplasma gondii from clinical specimens. The identification aids in the diagnosis of toxoplasmosis caused by the parasitic protozoanToxoplasma gondii and provides epidemiological information on this disease. Congenital toxoplasmosis is characterized by lesions of the central nervous system, which if undetected and untreated may lead to brain defects, blindness, and death of an unborn fetus. The disease is characterized in children by inflammation of the brain and spinal cord.(b)
Classification. Class II (performance standards).