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Wielisa MPO ANCA Test Kit. An Enzyme Linked Immunosorbent Assay (ELISA) for the detection and semi-quantitation of IgG antibodies in human serum to MPO (Myeloperoxidase). 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 Microscopic polyangiitis.

The Wielisa MPO ANCA Test Kit is an enzyme-linked immunosorbent assay (ELISA) for the detection and semi-quantitation of IgG antibodies to 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 microscopic polyangiitis. FOR IN VITRO DIAGNOSTIC USE.

The wells of the microtiter strips are coated with purified myeloperoxidase. 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 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 against a calibrator curve and the results are given in arbitrary units.

This submission describes the Wielisa MPO ANCA Test Kit, an ELISA for detecting and semi-quantitating IgG antibodies to myeloperoxidase (MPO) in human sera, used as an aid in diagnosing microscopic polyangiitis. While the document doesn't explicitly state "acceptance criteria", it provides performance metrics that serve as the basis for demonstrating substantial equivalence to a predicate device. The studies described assess the device's clinical sensitivity and specificity, relative sensitivity and specificity compared to other methods, and precision (batch-to-batch, inter-assay, intra-assay), and linearity.

Here's a breakdown of the acceptance criteria (inferred from the studies' findings) and the reported device performance:

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample sizes used for the test set and data provenance

   • Clinical Sensitivity and Specificity Study (Table 1):
     • Test Set Sample Size: 364 frozen retrospective sera.
     • Data Provenance: Retrospective sera. Country of origin is not specified but given the submitter is from Sweden, it is likely based in Europe or an international panel.
   • Comparison to P-ANCA IFA (Table 2):
     • Test Set Sample Size: 245 sera.
     • Data Provenance: Not explicitly stated as retrospective or prospective, but clinical characterization in other tables suggests a retrospective collection. Country of origin not specified.
   • Comparison to Alternate ELISA (Table 3):
     • Test Set Sample Size: 129 frozen retrospective sera.
     • Data Provenance: Retrospective sera. Country of origin not specified.

3. Number of experts used to establish the ground truth for the test set and qualifications of those experts

   • This information is not provided in the submission. The classification of patient groups (e.g., Microscopic Polyangiitis, Wegener's Granulomatosis, Systemic Lupus Erythematosus, Rheumatoid Arthritis, Anti-GBM nephritis, Healthy Normals) implies clinical diagnosis by medical professionals, but the number or specific qualifications of these "experts" (e.g., rheumatologists, nephrologists, pathologists) who established the ground truth are not detailed.

4. Adjudication method for the test set

   • This information is not provided in the submission. The ground truth seems to be based on pre-existing clinical characterization of the serum samples, but how these clinical diagnoses were adjudicated is not described.

5. Multi-reader multi-case (MRMC) comparative effectiveness study, effect size

   • No, an MRMC comparative effectiveness study involving human readers with and without AI assistance was not done. This device is an in vitro diagnostic (IVD) test kit (ELISA), not an AI-powered diagnostic imaging tool or a system designed to assist human readers in interpretation where an MRMC study would be applicable. The performance is assessed on the test's ability to detect an analyte directly.

6. Standalone (algorithm only without human-in-the-loop performance) study

   • Yes, the studies presented are effectively standalone performance studies for the device. The ELISA kit generates quantitative results (absorbance/units) that are interpreted against a cut-off (e.g., >20 units for positive) directly by the user, without a human "in the loop" for interpretation of the primary signal beyond reading the instrument output and applying the defined interpretation criteria. The device's output is the result.

7. The type of ground truth used

   • The ground truth for the clinical sensitivity and specificity study (Table 1) was based on clinical characterization of patient groups (e.g., diagnosed cases of microscopic polyangiitis, healthy normals, other autoimmune diseases).
   • For the comparative studies (Tables 2 & 3), the ground truth was the result from a predicate/comparative method:
     • P-ANCA IFA (for Table 2).
     • An alternate commercial MPO ANCA ELISA (for Table 3).

8. Sample size for the training set

   • This information is not provided in the document. The document describes the performance of the final device, but not its development process including how training sets (if any were used for assay development/optimization, calibration curve establishment) were utilized.

9. How the ground truth for the training set was established

   • As the sample size and details of a training set are not provided, how its ground truth was established is also not described. For an ELISA kit, "training" typically refers to the optimization of reagents, concentrations, and establishment of cut-off values and calibrator curves, often using well-characterized positive and negative control samples. However, the specifics of this process are not detailed in this submission.

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