Enzyme Immunoassay for the Detection of autoantibodies to SS-B in Human Serum.

Autoimmunity is characterized by the presence of antinuclear antibodies (ANA) against a multitude of macromolecules. Specific combinations of circulating ANA are used for diagnosis of the different types of autoimmune diseases. Therefore, identification of specific autoantibodies is important in the diagnosis and treatment of the disease. The nuclear antigen SS-B is believed to have a regulatory function in terminating the RNA transcription process. The presence of antibodies to SS-B correlates with that of SS-A. Anti-SS-B antibodies have been detected in approximately 60% of patients with Sjorgren's Syndrome and 25 - 30% of systemic lupus erythematosus (SLE). Additionally the presence of anti-SS-B antibodies has been associated with both systemic sclerosis and neonatal lupus. In recent years, immuno-diffusion has been the predominant method of choice for the detection of anti-SS-B antibodies; however, this technique has proven to be time-consuming, labor-intensive, and relatively insensitive. The MDI SS-B Test is an enzyme-linked immunosorbent assay, which in comparison to the immuno-diffusion method has the advantages of short incubations, increased sensitivity, and specificity.

SUMMARY OF 510 (k) SS-B

MDI SS-B Test reagents (P/N: SBKi-G) are intended for the semi-quantitative determination of IgG antibodies to SS-B in human serum. The principal diagnostic valueof this test is detection of autoantibodies, which are used as an aid in patients with rheumatoid diseases. The Micro Detect, Inc. SS-B reagent ( MDI SS-B 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 SS-B Test is substantially equivalent to those obtained by using predicate assays:

Relative Sensitivity: 94.6%

Relative Specificity: 97.7 %

Precision (%CV): 2.11- 4.68(Inter) and 1.88-5.99(Intra)

Stability: One year at 2-8 C. The stability of the MDI SS-B Test Kit for the detection of IgG antibodies to SS-B was found to be one year at 2-8 C. This was predicted from studies done under stress condition (37 C). Real time stability has only been monitored for ten weeks at 2-8 C. The MDI SS-B Test system is shown to be safe and effective and provide results, which are substantially equivalent to those, obtained by predicate products.