(36 days)
The Rheumatoid Factor assay is used for the quantitation of rheumatoid factor in human serum. Measurement of rheumatoid factor may aid in the diagnosis of rheumatoid arthritis.
Rheumatoid Factor is an in vitro diagnostic assay for the quantitative determination of rheumatoid factor in human serum. The RF assay is a latex enhanced immunoturbidimetric assay that involves an antigen-antibody reaction between the rheumatoid factor in the sample and the denatured human IgG, which has been adsorbed to latex particles. The resulting agglutination is detected as an absorbance change (572 nm), with the magnitude of the change being proportional to the quantity of RF in the sample. The actual concentration is then determined by interpolation from a calibration curve prepared from calibrators of known concentration.
The Abbott Laboratories Rheumatoid Factor assay is an in vitro diagnostic device for the quantitative determination of rheumatoid factor in human serum. The study described aimed to demonstrate the substantial equivalence of this device to a legally marketed predicate device, the Roche Diagnostics Corp. Tina-quant RF II assay.
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are implicitly derived from the comparison to the predicate device and the expected performance of such assays. The study primarily focused on correlation and precision, as well as the assay range and sensitivity.
| Performance Characteristic | Acceptance Criteria (Implicit) | Reported Device Performance (Abbott Rheumatoid Factor assay on AEROSET® System) |
|---|---|---|
| Correlation with Predicate Device (Roche Diagnostics Corp. Tina-quant RF II assay on Hitachi 717 Analyzer) | Strong positive correlation (e.g., correlation coefficient close to 1) | Correlation Coefficient: 0.996 |
| Slope: 1.14 | ||
| Y-intercept: 2.14 IU/mL | ||
| Precision (Total %CV) | Acceptable variability for clinical use across different levels (e.g., within-run, between-run, between-day) | Level 1: Total %CV ranged from 4.6% to 7.5% |
| Level 2: Total %CV ranged from 3.6% to 4.3% | ||
| Level 3: Total %CV ranged from 1.2% to 2.0% | ||
| Assay Range | Comparable to predicate device or suitable for clinical use | 4.8 to 200.0 IU/mL |
| Limit of Quantitation (Sensitivity) | Clinically relevant and comparable to predicate device | 7.71 IU/mL |
2. Sample Size Used for the Test Set and Data Provenance
The document does not explicitly state the sample size used for the comparative performance studies (test set). It mentions "comparative performance studies were conducted" and "On the AEROSET System," but specific numbers of patient samples are not provided. The data provenance is not explicitly stated (e.g., country of origin, retrospective or prospective).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
This information is not applicable and not provided in the document. The study involves comparing the analytical performance of two in vitro diagnostic (IVD) assays by measuring quantitative results. The "ground truth" in this context refers to the actual concentration of rheumatoid factor, which is determined by the assay itself, rather than expert interpretation of images or clinical outcomes that require expert consensus.
4. Adjudication Method for the Test Set
This information is not applicable and not provided in the document. As mentioned above, this study measures quantitative concentrations, not subjective interpretations requiring adjudication.
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. This type of study design is typically used for diagnostic imaging devices where human readers interpret images, sometimes with the assistance of AI, to determine diagnostic accuracy. This document describes an in vitro diagnostic assay that produces quantitative results, not an imaging device or a system requiring human interpretation.
6. If a Standalone (Algorithm Only Without Human-in-the-Loop Performance) Was Done
Yes, this study inherently represents a standalone performance. The Abbott Rheumatoid Factor assay, like other IVD assays, operates as an algorithm/instrument to produce a quantitative result. Its performance is measured independently based on its analytical capabilities (correlation, precision, range, sensitivity) with the input sample. There is no human-in-the-loop component for the measurement process itself.
7. The Type of Ground Truth Used
The ground truth for the comparison was the results obtained from the predicate device (Roche Diagnostics Corp. Tina-quant RF II assay on the Hitachi 717 Analyzer). For precision studies, the ground truth was derived from the known concentrations of control materials.
8. The Sample Size for the Training Set
This information is not applicable and not provided. The Abbott Rheumatoid Factor assay is an immunoassay, not a machine learning or AI-driven algorithm that requires a "training set" in the conventional sense for model development. Its calibration curve is established using calibrators, which are distinct from a training set for an AI model.
9. How the Ground Truth for the Training Set Was Established
This information is not applicable. As explained in point 8, there is no "training set" in the context of an AI/ML model for this type of immunoassay. The assay uses calibrators of known concentrations to establish its calibration curve, which allows for the interpolation of actual concentrations from measured absorbance changes. The ground truth for these calibrators would typically be established through highly accurate and traceable reference methods.
§ 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).