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510(k) Data Aggregation
(37 days)
This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection of autoantibodies to the antigen Proteinase 3 in human serum. The presence of PR-3 antibodies, in combination with clinical observations and other serological tests, can aid in the diagnosis of Wegener's granulomatosis (WG) and other conditions associated with elevated anti-neutrophil cytoplasmic antibodies (ANCA)
An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of autoantibodies to the antigen Proteinase 3 in human serum. The ELISA methodology is commonly used for serum antibody evaluations. Purified PR3 antigen has been attached to the inner surfaces of the microwell plate. During the initial incubation step, antibodies in patient serum bind specifically to the immobilized antigen and remain in place after a wash step. A second antibody which is conjugated to horseradish peroxidase (HRP) is used to recognize the "heavy + light" chain regions of the patient's antibodies remaining after the wash step. In the wells where the second antibody remains bound, the conjugated HRP catalyzes a color change in the substrate, tetramethyl benzidine (TMB). After the reaction is stopped, the color is read in an EIA Plate reader.
The provided 510(k) summary for K973823 describes a VIRGO® cANCA Kit, an enzyme-linked immunosorbent assay (ELISA) designed to detect autoantibodies to Proteinase 3 (PR3) in human serum. This test is intended as an aid in the diagnosis of current or past autoimmune-mediated vasculitides, specifically Wegener's granulomatosis.
Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:
1. Table of Acceptance Criteria and Reported Device Performance
The submission does not explicitly state pre-defined acceptance criteria in terms of specific sensitivity, specificity, or agreement percentages. Instead, the performance is reported as a comparison to a predicate device. The implied acceptance criterion is "substantial equivalence" to the predicate device, which is demonstrated by a high level of agreement.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance (VIRGO® cANCA Kit) |
|---|---|---|
| Comparative Testing | Substantial equivalence to the predicate device (Scimedx ANTI-PR3 ANTIBODY EIA), demonstrated by high agreement (sensitivity and specificity). | |
| Relative Sensitivity | N/A (implied high) | 100.0% (28/28) |
| Relative Specificity | N/A (implied high) | 100.0% (80/80) |
| Precision (Inter-assay) | Low coefficient of variation (%CV) | %CV for OD: 6.6% - 11.5%%CV for Units: 7.9% - 12.3% |
| Precision (Intra-assay) | Low coefficient of variation (%CV) | %CV for OD: 3.7% - 6.9%%CV for Units: 3.7% - 6.7% |
| Interfering Substances | No significant interference below specified concentrations | Hemoglobin < 500 mg/dL: No interferenceLipid < 20 mg/dL: No interferenceBilirubin < 3000 mg/dL: No interference |
| Prozone Effect | No unexpectedly low values with high-titered sera | Kit gives appropriately high positive results with high-titered sera. |
2. Sample Size Used for the Test Set and Data Provenance
- Test Set Size (Comparative Testing): A total of 108 serum specimens were used.
- Positive Panel: 28 samples from individuals with Wegener’s Granulomatosis.
- Normal Controls: 80 samples from apparently healthy donors.
- Data Provenance: The document does not explicitly state the country of origin. The study appears to be retrospective, using pre-existing serum specimens. The phrase "samples were used to assay" implies these were collected prior to the study for other purposes or as part of a biobank.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts
The document does not specify the number of experts used to establish the ground truth for the test set, nor does it detail their qualifications. The positive panel samples were "from individuals with Wegener’s Granulomatosis," implying a clinical diagnosis was the ground truth, but the details of this diagnosis (e.g., how many clinicians, their specialties, their experience) are not provided. Similarly, the "normal apparently healthy donors" imply a ground truth of healthy status, but how this was verified is not detailed.
4. Adjudication Method for the Test Set
The document does not mention any adjudication method for establishing the ground truth for the test set. It relies on the pre-existing classification of the samples (e.g., "from individuals with Wegener’s Granulomatosis").
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, If So, What Was the Effect Size of How Much Human Readers Improve with AI vs Without AI Assistance
This device is an in-vitro diagnostic (IVD) kit, specifically an ELISA. It does not involve "human readers" or "AI assistance" in the sense of image interpretation or decision support systems. Therefore, an MRMC comparative effectiveness study involving human readers and AI is not applicable to this type of device. The "reading" is an objective optical density measurement by an EIA Plate reader.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, this is essentially a standalone test in the context of IVDs. The "algorithm" is the ELISA assay methodology (binding, washing, enzymatic reaction, color change, OD measurement) and the established cutoff value. The performance metrics (sensitivity, specificity, precision) reflect the algorithm's performance in detecting the target analytes in the absence of human "interpretation" beyond reading the OD value and comparing it to a cutoff. The "human-in-the-loop" would be the clinician interpreting the result in the context of the patient's overall clinical picture, but the performance data presented is for the assay itself.
7. The Type of Ground Truth Used
The ground truth used for the comparative testing was clinical diagnosis.
- For the positive panel: "individuals with Wegener's Granulomatosis."
- For the negative/normal panel: "normal apparently healthy donors."
The document does not indicate the use of pathology or specific outcomes data to establish this ground truth, beyond the clinical diagnosis.
8. The Sample Size for the Training Set
The document does not explicitly mention a separate "training set" for the VIRGO® cANCA Kit. For IVD assays, the development process involves optimization and establishment of parameters (like cutoff values), but these are typically part of the assay development phase rather than a formally described "training set" in the context of machine learning. The studies described are performance validation studies.
9. How the Ground Truth for the Training Set Was Established
Since a dedicated "training set" is not explicitly mentioned, the method for establishing its ground truth is not provided. If the question refers to how the assay's cutoff was established, the document does not detail this. It only states that the device "utilizes optical density as a measure of antibody presence, with an established cutoff between a positive and a negative reaction."
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