Description

The Diagnostic Automation Inc. Autoimmune EIA Anti-dsDNA ELISA kit is a quantitative enzyme immunoassay (EIA) intended to screen for the presence of dsDNA antibodies in human serum as an aid in the diagnosis of systemic lupus erythematosus (SLE). This kit is for in vitro diagnostic use.

Antinuclear antibodies (ANAs) directed against a variety of macromolecules occur in extraordinarily high frequency in systemic rheumatic diseases. Many rheumatic diseases are characterized by the presence of one or more of these ANAs. Therefore, the identification of the specific antibody is useful in the detection and diagnosis of the disease. Anti-dsDNA is present in 50-70% of patients with SLE. Circulating DNA/anti-DNA immune complexes are considered to play a part in the pathogenesis of SLE. The presence of anti-dsDNA is one of the diagnostic criteria for SLE. IgG antibodies to dsDNA are considered clinically most useful for the diagnosis and management of SLE. Antibodies to single stranded DNA (ssDNA) and IgM antibodies to dsDNA are found in a number of other connective diseases, liver diseases, as well as in some normal individuals. Accurate detection of anti-dsDNA is important in the diagnosis and management of SLE. EIA tests for anti-dsDNA have demonstrated greater sensitivity than standard IFA and RIA tests allowing for improved detection of low titer antibodies to dsDNA.

Purified dsDNA is bound to microwells. The DNA retains its antigenicity and remains double stranded. Antibodies to dsDNA, if present in diluted serum, bind in the microwells. Washing of the microwells removes unbound serum antibodies. Horseradish peroxidase (HRP) conjugated anti-human IgG immunologically binds to the bound patient antibodies forming a \"conjugate - anti-dsDNA - dsDNA\" sandwich. Washing of the micro- wells removes unbound conjugate. An enzyme substrate in the presence of bound conjugate hydrolyzes to form a blue color. The addition of an acid stops the reaction, forming a yellow end product. The intensity of the color is measured photometrically at 450 nm.