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The Varelisa® ReCombi ANA Screen EIA kit is designed for the qualitative determination of eight antinuclear antibodies in human serum or plasma to aid in the diagnosis of systemic rheumatic diseases such as SLE (Systemic Lupus Erythematosus), Scleroderma (Progressive Systemic Sclerosis), MCTD (Mixed Connective Tissue Disease), SS (Sjögren's Syndrome) and Polymyositis/ Dermatomyositis. The Varelisa ReCombi ANA Screen detects antibodies against dsDNA, RNP(68kDa, A, C), Sm(B,B',D) SS-A/Ro(52kDa, 60kDa), SS-B/La, Scl-70, Centromere and Jo-1 in a single microwell.

The Varelisa ReCombi ANA Screen is an enzyme immunoassay for the qualitative determination of antinuclear antibodies in serum or plasma. Designed as a screen assay, it detects 8 antinuclear antibodies in a single microwell. The determination of antinuclear antibodies (ANA) is of central importance for the clinical diagnosis of rheumatic diseases. The presence of ANA suggests the possibility of rheumatic autoimmune diseases. These diseases include Systemic Lupus Erythematosus, Polymyositis/ Dermatomyositis, Scleroderma, Sjögren's Syndrome and Mixed Connective Tissue Diseases.

Varelisa ReCombi ANA Screen is an indirect noncompetitive enzyme immunoassay. The wells of a microplate are coated with human recombinant, native affinity purified nuclear antigens and dsDNA. Antibodies specific for the nuclear antigens present in a patient sample bind to these antigens.

In a second step the enzyme labeled second antibody (Conjugate) binds to the antigenantibody complex which leads to the formation of an enzyme labeled antigen-antibody sandwich complex.

The enzyme labeled antigen-antibody complex converts the added substrate to form a colored solution. The rate of color formation from the chromogen is a function of the amount of Conjugate complexed with the bound antibody and thus is proportional to the initial concentration of the respective antibodies in the patient sample.

1. Acceptance criteria and reported device performance:

Note: The acceptance criteria are largely implied by the nature of a 510(k) submission, which focuses on demonstrating substantial equivalence to a predicate device. The primary performance metric presented is the agreement rate and correlation with the predicate device.

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

• Sample Size for the Test Set: 129 samples.
• Data Provenance: The document does not specify the country of origin. It is a retrospective study comparing a new device to an existing predicate device using collected samples.

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

This information is not provided in the summary. The study is a comparison between two devices, not an evaluation against an independent gold standard established by experts.

4. Adjudication method for the test set:

This information is not provided in the summary. Given it's a direct comparison between two assays, an adjudication method for reconciling differences between human readers or separate ground truth methodologies isn't applicable in the same way it would be for image-based or interpretation-heavy diagnostic studies. The "adjudication" in this context involved the exclusion of 7 dsDNA positive samples due to the known difference in detectable analytes between the new device and the predicate.

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, an MRMC comparative effectiveness study was not done. This study is for an in vitro diagnostic (IVD) immunoassay, not an AI-powered diagnostic imaging device that involves human reader interpretation. Therefore, the concept of human readers improving with AI assistance is not applicable here.

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

Assuming "standalone" refers to the device's inherent performance without human interpretation influencing the measurement, yes, a standalone performance study was done in the sense that the Varelisa ReCombi ANA Screen (and the predicate device) are automated or semi-automated laboratory assays that quantitatively or qualitatively measure analytes in a sample. The results are generated by the device itself based on the reaction, rather than requiring human interpretation of complex outputs in the way an imaging AI might. The study directly compares the results from the new device to the predicate device.

7. The type of ground truth used:

The "ground truth" for this study was essentially the results obtained from the predicate device, Varelisa® ANA-8-Screen Assay, for the analytes it detects. For the dsDNA specificity, the ground truth was the known characteristic of the new device to detect dsDNA, which the predicate did not. This is a comparative study, not one establishing absolute diagnostic accuracy against a clinical outcome or pathology.

8. The sample size for the training set:

This information is not provided in the summary. This appears to be a clinical validation study for a finished device, not a development or training phase for a machine learning model.

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

This information is not provided in the summary, as there is no mention of a training set or a machine learning component for this device.

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