Search Results

This enzyme-linked immunosorbent assay (ELISA) is indicated for the detection and measurement of circulating IgA antibodies to ß₂ Glycoprotein I in human serum. The presence of these antibodies, in combination with clinical observations and other laboratory findings, is intended to aid in the diagnosis of Antiphospholipid Syndrome.

An enzyme-linked immunosorbent assay (ELISA) designed for the detection and measurement of IgA antibodies to ß₂ Glycoprotein I in human serum. The ELISA methodology is commonly used for serum antibody evaluations. Purified human ß₂ glycoprotein has been attached to the inner surfaces of the microwell plate. During the initial incubation step, specific antibodies in patient serum will bind to the antigen and are immobilized on the surface. After incubation and a wash step, a peroxidase labeled anti human IgA (α chain specific) second antibody is added to the wells to react with the immobilized anti beta 2 GP1 antibodies. After incubation and another wash step, the substrate is added. In the wells where the specific antigen-antibody-HRP complex remains bound, the peroxidase enzyme catalyzes a color change in the substrate. After the enzymatic reaction is stopped, the colored product is read in an EIA plate reader at a specified wavelength.

Here's a breakdown of the acceptance criteria and study details for the VIRGO® β₂ Glycoprotein I IgA Antibody Kit, based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined acceptance criteria for the performance studies in terms of specific sensitivity, specificity, or agreement thresholds. Instead, it presents the results of these performance tests as evidence of the device's effectiveness.

2. Sample Sizes and Data Provenance

• Test Set Sample Size:
  • Performance Testing (Clinical Samples):
    • APS (Primary): 43
    • SLE + APS: 7
    • SLE (No APS): 20
    • Scl-70 (No APS): 20
    • Infectious: 80
    • Normals: 120
    • Total for Clinical Samples: 290
  • Comparative Study (vs. aCL IgA):
    • Clinically characterized serum samples: 50
    • Apparently healthy donors: 30
    • Total for Comparative Study: 80
• Data Provenance: The document states "clinically characterized serum specimens from individuals diagnosed with Primary APS and other diseases" and "serum samples from apparently healthy donors." It does not specify the country of origin. The data is retrospective, as the samples were "characterized" prior to being tested with the device.

3. Number of Experts and Qualifications

The document does not provide information on the number of experts used to establish the ground truth for the test set or their qualifications. It only states that the samples were "clinically characterized" or from individuals "diagnosed" with specific conditions.

4. Adjudication Method

The document does not mention any adjudication method (e.g., 2+1, 3+1, none) for establishing the ground truth of the test set.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, a multi-reader multi-case (MRMC) comparative effectiveness study was not conducted. This device is an in vitro diagnostic (IVD) assay, not an imaging or diagnostic AI requiring human interpretation. Therefore, the concept of "human readers improve with AI vs. without AI assistance" does not apply.

6. Standalone Performance

Yes, a standalone (algorithm only) performance study was done. The precision studies (Inter Assay and Intra Assay) and the performance testing with clinically characterized serum samples (reporting percentages positive in various patient groups) demonstrate the device's performance in a standalone capacity. The comparative study against a commercial aCL IgA EIA assay also reflects the device's standalone performance relative to another diagnostic method.

7. Type of Ground Truth Used

The ground truth for the clinical samples was based on clinical diagnosis ("individuals diagnosed with Primary APS and other diseases") and status for healthy individuals ("30 serum samples from apparently healthy donors"). The "infectious group consisted of samples with positive syphilis serology."

8. Sample Size for the Training Set

The document does not provide information on the sample size for a training set. This is typical for an IVD device of this nature from this era, where the "training" (development and calibration) would often involve different types of internal analytical studies rather than a distinct, separate "training set" as understood in modern machine learning.

9. How Ground Truth for Training Set Was Established

As no training set is explicitly mentioned or utilized in the sense of a machine learning algorithm, there is no information on how its ground truth was established. The "training" for such an assay typically involves establishing appropriate assay parameters, calibrator values, and cut-offs, often using a combination of analytical studies and preliminary clinical samples. The "Cal Dil" samples and other control materials mentioned in the precision studies would be part of this process.

Ask a specific question about this device