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This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection of altoantilian to the antigen Myeloperoxidase (MPO) in human serum. The presence of MPO antibodies, in combination with dinical observations and other serological tests, can aid in the dlagnosis of polyarterits, necrotizing glomerulonephritis 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 myeloperoxidase in human serum.

The ELISA methodology is commonly used for serum antibody evaluations. Purified MPO 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.

Here's a breakdown of the acceptance criteria and study details for the K973824 device, based on the provided 510(k) summary:

1. Table of Acceptance Criteria and Reported Device Performance

The 510(k) summary for K973824 primarily focuses on demonstrating substantial equivalence to a predicate device rather than explicitly stating pre-defined acceptance criteria with numerical targets. However, the performance data presented implies the following implicit criteria for comparison with the predicate:

2. Sample Size Used for the Test Set and Data Provenance

• Comparison Testing:

  • Total samples: 132 serum specimens.
  • Breakdown:
    • 22 pANCA positive specimens (from throughout the United States).
    • 40 specimens from individuals demonstrating pauci-immune necrotizing and/or crescentic glomerulonephritis.
    • 70 specimens from normal apparently healthy donors.
  • Provenance: Retrospective, as indicated by collecting "specimens taken from throughout the United States" and from "individuals demonstrating" certain conditions. The specific country of origin is "United States" for at least the pANCA positive samples.

• Precision Studies:

  • Inter-assay: 7 samples, assayed in duplicate twice a day for 5 days (70 individual measurements per sample set).
  • Intra-assay: 7 samples, assayed 20 consecutive times in a single run (140 individual measurements per sample set).
  • Provenance: Not explicitly stated, but typically these are controlled laboratory samples, not necessarily patient samples.

• Interfering Substances: Specific number of samples not given, but mentioned as "Libemic, icteric, and hemolytic samples were evaluated."

• Prozone: "several high titered serum samples" were used.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

The document does not explicitly state the number of experts or their qualifications used to establish the ground truth for the test set.

4. Adjudication Method (e.g., 2+1, 3+1, none) for the Test Set

The document does not describe any specific adjudication method for establishing the ground truth of the test set. The ground truth for the comparison testing was based on the results of the "predicate device" and in eight discrepant cases, confirmed by a "third party IFA kit."

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

No, a Multi Reader Multi Case (MRMC) comparative effectiveness study was not done. This device is an in-vitro diagnostic (IVD) assay kit for laboratory use, not an AI-assisted diagnostic tool for human readers. Therefore, the concept of human readers improving with or without AI assistance does not apply.

6. If a Standalone (i.e. algorithm only without human-in-the-loop performance) was done

This device is a standalone in-vitro diagnostic (IVD) assay kit. Its performance is evaluated biochemically (optical density measurements) rather than through an algorithm. The reported performance metrics (sensitivity, specificity, precision) reflect the device's standalone capability to detect and measure autoantibodies.

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

The ground truth for the comparison testing was established using:

• Results from the predicate device (Scimedx MPO ANTIBODY EIA Kit).
• For discrepant samples (8 cases), confirmation was made by a third-party IFA kit.
• The selection of samples also involved clinical categories: "pANCA positive specimens," "specimens from individuals demonstrating pauci-immune necrotizing and/or crescentic glomerulonephritis," and "normal apparently healthy donors." This implies a degree of clinical diagnosis informing the sample classification.

8. The Sample Size for the Training Set

The document does not specify a separate "training set" for the device development. IVD kits typically undergo development and optimization, but the concept of a distinct 'training set' as used in machine learning is not directly applicable or documented here. The reported "Performance Data" is for validation.

9. How the Ground Truth for the Training Set Was Established

As no explicit training set is detailed, the method for establishing its ground truth is not applicable or provided. Device development and optimization for such kits usually involve internal standards, known positive/negative controls, and research samples.

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