(65 days)
The Wielisa ANCA Screening Test Kit is an enzyme-linked immunosorbent assay (ELISA) for the qualitative detection of antibodies to Proteinase-3 (PR-3) and Myeloperoxidase (MPO) in human sera. The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of systemic vasculitis, especially Wegener's granulomatosis (WG) and microcopic polyangiitis (MP). The assay is intended for use in patients with signs and symptoms consistent with systemic vasculitis. It is not intended for screening a healthy population. A positive result should always be confirmed by a semi-quantitative assay.
The Wielisa ANCA Screening Test Kit is an enzyme-linked immunosorbent assay (ELISA) for the qualitative detection of antibodies to Proteinase-3 (PR-3) and Myeloperoxidase (MPO) in human sera. The assay is used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of systemic vasculitis, especially Wegener's granulomatosis (WG) and microcopic polyangiitis (MP). The assay is intended for use in patients with signs and symptoms consistent with systemic vasculitis. It is not intended for screening a healthy population. A positive result should always be confirmed by a semi-quantitative assay.
The wells of the microtiter strips are coated with purified (Human Neutrophil source) proteinase 3, and MPO (Human Neutrophil source) antigen. During the first incubation, specific antibodies in diluted serum, will bind to the antigen coating.
The wells are then washed to remove unbound antibodies and other components. A conjugate of alkaline phosphatase-labeled (Goat) antibodies to human IgG binds to the antibodies in the wells in this second incubation.
After a further washing step, detection of specific antibodies is obtained by incubation with substrate solution. The amount of bound antibodies correlates to the color intensity and is measured in terms of absorbance (optical density (OD)). The absorbance is then calculated and the results are given as a ratio to the negative control.
Here's an analysis of the acceptance criteria and study detailed in the provided document:
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 or specificity. However, it presents the results of a comparative study against clinical characterization and a predicate semi-quantitative ELISA. We can infer the performance targets based on the documented predicate device equivalence. For the purpose of this response, I'll interpret the "acceptance criteria" as meeting or exceeding the performance of the predicate devices or demonstrating high clinical validity.
| Performance Metric | Specificity/Threshold | Acceptance Criteria (Inferred) | Reported Device Performance |
|---|---|---|---|
| Clinical Sensitivity - PR3-ANCA | WG samples | High (e.g., >80%) | 92.9% (95% CI: 84.9-100%) |
| MP samples | Moderate (e.g., >50%) | 51.2% (95% CI: 35.6-66.8%) | |
| Clinical Sensitivity - MPO-ANCA | WG samples | Low (e.g., 40%) | 46.5% (95% CI: 31.3-61.7%) |
| Clinical Specificity - PR3-ANCA | SLE | Very High (e.g., >95%) | 100% (95% CI: 90.4-100%) |
| RA | Very High (e.g., >95%) | 100% (95% CI: 92.7-100%) | |
| NS (Blood Donors) | Very High (e.g., >95%) | 100% (95% CI: 97.6-100%) | |
| Clinical Specificity - MPO-ANCA | SLE | High (e.g., >80%) | 82.8% (95% CI: 68.7-96.8%) |
| RA | Very High (e.g., >95%) | 100% (95% CI: 92.6-100%) | |
| NS (Blood Donors) | Very High (e.g., >95%) | 100% (95% CI: 97.6-100%) | |
| Relative Sensitivity - PR3-ANCA (vs. Semi-quantitative ELISA) | (Implied equivalence) | High (e.g., >95%) | 98.3% (95% CI: 95.0-100%) |
| Relative Sensitivity - MPO-ANCA (vs. Semi-quantitative ELISA) | (Implied equivalence) | High (e.g., >95%) | 95.8% (95% CI: 87.7-100%) |
| Relative Specificity - PR3-ANCA (vs. Semi-quantitative ELISA) | (Implied equivalence) | Very High (e.g., >98%) | 100% (95% CI: 98.0-100%) |
| Relative Specificity - MPO-ANCA (vs. Semi-quantitative ELISA) | (Implied equivalence) | Very High (e.g., >98%) | 100% (95% CI: 98.4-100%) |
| Batch to Batch Variation (CV%) | PR3-ANCA | Low (e.g., |
§ 866.5660 Multiple autoantibodies immunological test system.
(a)
Identification. A multiple autoantibodies immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoantibodies (antibodies produced against the body's own tissues) in serum and other body fluids. Measurement of multiple autoantibodies aids in the diagnosis of autoimmune disorders (disease produced when the body's own tissues are injured by autoantibodies).(b)
Classification. Class II (performance standards).