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The Diamedix Is anti-β ,Glycoprotein | IgG/IgM Test Kit is indications for OSS inmunoassay (EIA) for the semi-quantitative measurement of IgG or IgM antibodies to ßglycoprotein I in human serum as an aid in the diagnosis of certain autoimmune disease thrombotic disorders in patlents with SLE or SLE-like disorders. These reagents can be used either manually or in conjunction with the MAGO® Plus Automated EIA Processor.

The Is anti-β, Glycoprotein I IgG/IgM Test System is an enzyme-linked immunosorbent assay (ELISA) for the semi-quantitative measurement of IgG or IgM antibodies to ß, glycoprotein in human serum

The Diamedix Is anti-β₂Glycoprotein I IgG/IgM Test System is an enzyme-linked immunosorbent assay (ELISA) designed for the semi-quantitative measurement of IgG or IgM antibodies to β₂-glycoprotein in human serum. It is intended for use as an aid in the diagnosis of certain autoimmune disease thrombotic disorders in patients with SLE or SLE-like disorders.

Acceptance Criteria and Device Performance

The provided document describes several performance characteristics of the device, including:

1. Relative Sensitivity and Specificity (compared to commercially available ELISA kits)

2. Clinical Sensitivity and Specificity (against clinically characterized sera)

3. Precision (Intra-assay and Inter-assay Coefficient of Variation - CV%)

No explicit acceptance criteria for CV% are stated. However, typical expectations for ELISA precision would be CV% values generally below 15-20%, especially for higher concentration samples. The reported precision values are generally within acceptable ranges for immunoassays.

Manual Intra-assay and Interassay Precision for Is-anti-B₂-Glycoprotein I IgG (Selected CV% Values):

• Intra-assay (Range): 0.22% - 14.09%
• Interassay (Range): 2.26% - 9.82%

MAGO Plus - Intra-assay and Interassay Precision for Is-anti-B₂-Glycoprotein I IgG (Selected CV% Values):

• Intra-assay (Range): 1.12% - 22.35%
• Interassay (Range): 4.84% - 24.13%

Manual Intra-assay and Interassay Precision for Is-anti-B₂-Glycoprotein IgM (Selected CV% Values):

• Intra-assay (Range): 0.00% - 19.52%
• Interassay (Range): 3.92% - 17.15%

MAGO Plus - Intra-assay and Interassay Precision for Is-anti-B₂-Glycoprotein IgM (Selected CV% Values):

• Intra-assay (Range): 1.93% - 20.33%
• Interassay (Range): 9.89% - 19.77%

Study Details

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

• 3-point vs 6-point calibration:
  • 178 samples for IgG
  • 187 samples for IgM
• Relative Sensitivity and Specificity:
  • 172 frozen retrospective sera for IgG antibodies.
  • 161 frozen retrospective sera for IgM antibodies.
  • Data Provenance: Retrospective, no country of origin specified.
• Clinical Sensitivity and Specificity:
  • 388 frozen retrospective, clinically characterized sera. These included:
    • 248 normal sera
    • 57 sera from patients with diagnosed anti-phospholipid syndrome (APS)
    • 33 sera from patients with systemic lupus erythematosus (SLE)
    • 35 sera from patients with other autoimmune diseases (Sjogren's Syndrome, scleroderma, polymyositis/dermatomyositis)
    • 15 samples from patients with positive RPR titers
  • Data Provenance: Retrospective, no country of origin specified.
• Cross-Reactivity:
  • 50 samples reactive to various autoantibodies (SSA/SSB, Scl-70, Jo-1, dsDNA, RF, RPR positive).
• Linearity:
  • "Several highly positive samples" serially diluted.
• Correlation of Manual and MAGO Plus results:
  • 153 serum samples for anti-B₂ glycoprotein I IgG antibodies.
  • 163 sera for anti-B₂ glycoprotein I IgM antibodies.
• Precision:
  • 6 serum samples of varying reactivity tested in triplicate in three separate runs for both manual and MAGO Plus methods.
• Expected Values (Normal Population):
  • 148 S. Florida blood donors.
  • Data Provenance: Prospective (presumably from healthy donors), South Florida, USA.
• Expected Values (Clinical Population):
  • 57 sera from patients with a diagnosis of anti-phospholipid syndrome (APS).

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

• The document does not explicitly state the number of experts or their qualifications for establishing ground truth.
• For "Relative Sensitivity and Specificity," a "refereed EIA method" was used to resolve discordant samples, implying expert interpretation or confirmation of the referee test results, but without specifying the number or qualifications of experts.
• For "Clinical Sensitivity and Specificity," samples were described as "clinically characterized sera," implying a diagnosis by medical professionals, but again, without details on the number or specific qualifications of these clinicians.

4. Adjudication method for the test set:

• For "Relative Sensitivity and Specificity," discordant samples (between the test device and the "other EIAs") were sent for "further resolution" by a "referee EIA method." This implies an adjudication process where a third, presumably more definitive, method was used for discordant results. No specific "X+Y" adjudication rule is mentioned for expert review.

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 MRMC comparative effectiveness study was done. This device is an in-vitro diagnostic (IVD) assay, not an AI or imaging device involving human readers for interpretation. Its performance is evaluated biochemically, not through human reader interpretation of images or other data.

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

• Yes, the device was evaluated in a standalone manner. It is an ELISA test system that directly measures antibodies in serum. Its performance characteristics (sensitivity, specificity, precision, linearity, etc.) are inherent to the assay and its components, functioning "algorithm only" in the sense of a biochemical procedure. The document discusses both "manual" and "MAGO Plus Automated EIA Processor" usage, with the latter being automated, further supporting the standalone evaluation of the device's technical performance.

7. The type of ground truth used:

• Relative Sensitivity and Specificity: The ground truth was established by comparing the device's results against "commercially available ELISA kits" and, for discordant samples, a "referee EIA method." This is a comparative ground truth based on other established assay methods.
• Clinical Sensitivity and Specificity: The ground truth was based on "clinically characterized sera" from patients with diagnosed conditions (APS, SLE, other autoimmune diseases) or normal individuals. This represents a clinical diagnosis ground truth, implying that patients' disease status was determined by standard medical diagnostic procedures and clinical presentation.
• Cross-Reactivity: Ground truth was based on samples "reactive to various autoantibodies."
• Expected Values: Ground truth was based on "normal, healthy population" (blood donors) and "patients with a diagnosis of anti-phospholipid syndrome (APS)."

8. The sample size for the training set:

• The document does not explicitly mention a "training set" in the context of machine learning or AI. This is a traditional IVD device. The samples used for calibration (3-point vs 6-point) and for various performance studies (relative sensitivity/specificity, clinical sensitivity/specificity, precision, etc.) serve as validation data for the assay's performance characteristics. The assay is likely developed with internal validation data, but these details are not provided in a summary for regulatory submission.

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

• As this is not an AI/ML device, the concept of a "training set" with ground truth in that specific context does not apply. The development of the assay would involve internal R&D with characterized samples and controls to optimize reagents and procedures, which implicitly establishes "ground truth" for the internal optimization process. However, the document focuses on the validation studies for regulatory submission, as outlined in point 7.

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