Intended use

The DIASTAT^® anti-nuclear antibody (ANA) test is a qualitative enzyme-linked immunosorbent assay (ELISA) for the detection of ANAs in human serum or EDTA plasma. It detects ANAs against Sm, Sm/RNP, Ro (SS-A), La (SS-B), Scl-70, Jo-1, dsDNA, histone and centromere antigens.

The test may be used for screening to eliminate samples negative for all ANAs. Samples that give a positive test result should be further tested to identify the antigen-specific antibody or antibodies present.

Background

Detection and serological characterisation of specific autoantibodies play an important role in the differential diagnosis of systemic rheumatic diseases. Autoantibodies to nuclear antigens (ANAs) are a group of antibodies specific for nuclear antigens including Sm, Sm/RNP, Ro (SS-A), La (SS-B), Scl-70, Jo-1, dsDNA, histone and centromere antigens. A positive ANA test result provides presumptive evidence for systemic rheumatic disease and further definition of specific antibody profiles is a valuable aid in the diagnostic process. A negative result reduces, but does not exclude, the likelihood of systemic rheumatic disease.
 

Technical information

The wells of the microtitre strips are coated with highly purified HEp-2 cell extract. During the first incubation, specific ANAs in diluted serum or EDTA plasma bind to the antigen-coated surface. The wells are then washed to remove unbound components. In the second incubation, the Conjugate, enzyme-labelled antibodies to human IgG and IgM, binds any surface-bound autoantibodies. After further washing, specific autoantibodies are traced by incubation with the Substrate. Addition of Stop Solution terminates the reaction, resulting in a coloured end-product. The amount of Conjugate bound is measured in absorbance units and compared with that bound by the Reference Control.