Enzyme Immunoassay for the Detection of Autoantibodies to ds-DNA in Human Serum.

Systemic rheumatic diseases are characterized by the presence of antinuclear antibodies (ANA) against a multitude of macromolecules. Specific combinations of circulating ANA are the distinctive features of the different types of autoimmune diseases. Therefore, identification of specific auto antibodies is important in the diagnosis and treatment of the disease.

Antibodies to ds-DNA are present in 60-70% of patients with systemic lupus erythematosus (SLE), and ds-DNA/anti ds-DNA immune complexes have implicated in the pathogenesis of SLE. Low levels of anti ds-DNA antibodies are associated with a number of rheumatic diseases although these antibodies occur in 2-3% of individuals with no symptoms of rheumatic disease. There is also evidence that anti ds-DNA antibodies may appear prior to the development of clinical symptoms of rheumatic diseases and may therefore aid in the early diagnosis of such diseases.

In recent years, a variety of different techniques have been utilized to detect anti ds-DNA antibodies; these include radioimmunoassays, immunofluorescent assays, and solid phase enzyme immunoassays; however, such techniques have demonstrated varying degrees of sensitivity, specificity, and precision. The Micro Detect anti ds-DNA Test is an EIA technique, which has the advantages of short incubations, increased sensitivity, and specificity.

SUMMARY OF 510 (k)

MDI ds-DNA Test reagents (P/N: dsKi-M&G) are intended for the semi-quantitative determination of IgG & IgM antibodies to ds-DNA in human serum. The principal diagnostic value of this test is detection of autoantibodies, which are used as an aid in patients with rheumatoid diseases.

The Micro Detect, Inc. ds-DNA reagent ( MDI ds-DNA Test) is intended to be used as a manual procedure. The reagents are supplied as a micro plate coated with specific antigens and Controls, Wash Buffer, Sample Diluent, Conjugate, Substrate, and Stop Solution.

The patient results obtained using the MDI ds-DNA Test is substantially equivalent to those obtained by using a predicate assay:

Relative Sensitivity: 100%

Relative Specificity: 96.4 %

Precision (%CV): 2.07- 4.18 (Inter) and 1.58- 5.01(Intra)

Stability: The stability of the MDI ds-DNA Test Kit for the detection of IgM & IgG antibodies to ds-DNA was found to be one year at 2-8 C.

The MDI ds-DNA Test system is shown to be safe and effective and provide results, which are substantially equivalent to those, obtained by predicate products.