(49 days)
The test provides qualitative and semi-quantitative determination of rheumatoid factors (RF) in human serum. The test provides results for one of the seven criteria used in the diagnosis of rheumatoid arthritis as suggested by the American College of Rheumatology
ColorSlide® RF is a rapid latex particle agglutination assay for the determination of circulating Rheumatoid Factors (RF) in human serum.
The provided text describes the Seradyn ColorSlide® RF device and its performance in comparison to predicate devices, SeraTest™ RF and Behring's Rapitex RF.
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state pre-defined acceptance criteria in terms of numerical thresholds for sensitivity, specificity, and efficiency. Instead, it states that "An acceptable correlation was obtained between the two tests" (ColorSlide® RF vs. SeraTest™ RF and ColorSlide® RF vs. RapiTex RF). The reported performance values are:
Comparison to SeraTest™ RF (Qualitative Assay)
| Metric | Reported Performance |
|---|---|
| Relative Sensitivity | 100% |
| Relative Specificity | 97.9% |
| Positive Predictive Value | 98.2% |
| Negative Predictive Value | 100% |
| Efficiency of Test | 99.03% |
Comparison to RapiTex RF (Qualitative Assay)
| Metric | Reported Performance |
|---|---|
| Relative Sensitivity | 97.69% |
| Relative Specificity | 98.32% |
| Positive Predictive Value | 97.69% |
| Negative Predictive Value | 98.32% |
| Efficiency of Test | 98.06% |
Semi-Quantitative Agreement
| Comparison | Agreement Type | Reported Performance (ColorSlide® RF vs. SeraTest™ RF) | Reported Performance (ColorSlide® RF vs. RapiTex RF) |
|---|---|---|---|
| Complete Agreement | Exact Titer | 28.6% (16/56 samples) | 47.37% (63/133 samples) |
| +/- One Dilution | Within one titer | 55.4% (31/56 samples) | 48.12% (64/133 samples) |
| > One Dilution | 16.1% (9/56 samples) | 4.5% (6/133 samples) |
Lot-to-Lot Reproducibility: All titers fell within one doubling dilution, indicating satisfactory performance with little or no lot-to-lot variability.
Sensitivity based on international standard: Approximately 20 IU/mL, traceable to a WHO reference serum.
Passive Interference: No adverse interference from hemoglobin (at 1000 mg/dL), bilirubin (at 40 mg/dL), or lipid (at 20 g/L).
Stability Data: Performance within specifications for approximately 400 days for one ColorSlide® RF lot, with ongoing studies for at least two years.
2. Sample Size Used for the Test Set and Data Provenance
- Comparison to SeraTest™ RF:
- Sample Size: 103 patient samples.
- Data Provenance: Testing was conducted at one site. The country of origin is not specified but is implicitly the USA, given the company's address and the FDA 510(k) submission. It's a retrospective comparison study, as patient samples were tested by both methods.
- Comparison to Behring's RapiTex RF:
- Sample Size: 309 patient samples.
- Data Provenance: Testing was conducted at three sites. Country of origin implicitly USA. Retrospective comparison study.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications
The studies compare the ColorSlide® RF device to two legally marketed predicate devices (SeraTest™ RF and RapiTex RF). The ground truth for sensitivity and specificity is established by the results of these predicate devices. The document does not mention the involvement of "experts" in establishing a separate ground truth or their qualifications. The readings of the agglutination reactions for both the ColorSlide® RF and the predicate devices are "read visually," implying trained laboratory personnel but no specifically defined "experts" for ground truth establishment.
4. Adjudication Method for the Test Set
No explicit adjudication method is described. The comparison is made directly between the results of the ColorSlide® RF and the predicate device. For the semi-quantitative assay, agreement is categorized. There is no mention of a process like 2+1 or 3+1 for resolving discrepancies.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
No MRMC comparative effectiveness study was done. The document does not describe human readers using AI assistance or measuring its effect size. The device is a diagnostic assay, not an AI software.
6. Standalone (Algorithm Only) Performance
The device is a laboratory assay (latex agglutination test), not an algorithm or AI software. Therefore, the concept of "standalone performance" in the context of an algorithm does not apply. Its performance is inherent in the chemical and physical reaction, read visually by laboratory personnel.
7. Type of Ground Truth Used
The ground truth for the performance assessment (sensitivity, specificity, predictive values) is established by the results of the predicate devices (Seradyn's SeraTest™ RF and Behring's Rapitex RF). For the semi-quantitative assays, the ground truth for agreement is also based on the titers obtained from the predicate devices. The document does not mention pathology, outcomes data, or expert consensus as primary ground truth references for the clinical performance assessment.
8. Sample Size for the Training Set
This information is not applicable. The ColorSlide® RF is a latex agglutination assay, not an AI or machine learning algorithm that requires a "training set." Its development would involve chemical and manufacturing processes, and its characteristics are assessed against established methods, not by training.
9. How the Ground Truth for the Training Set was Established
As mentioned above, there is no "training set" in the context of an AI/ML algorithm. Therefore, this question is not applicable to the ColorSlide® RF device. The assay development would have involved validation against known positive and negative samples, but these are part of R&D and not typically referred to as a "training set" in this context.
§ 866.5775 Rheumatoid factor immunological test system.
(a)
Identification. A rheumatoid factor immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the rheumatoid factor (antibodies to immunoglobulins) in serum, other body fluids, and tissues. Measurement of rheumatoid factor may aid in the diagnosis of rheumatoid arthritis.(b)
Classification. Class II (performance standards).