Comparison of three multiplex immunoassays for detection of antibodies to extractable nuclear antibodies using clinically defined sera.

We set out to determine the agreement of three multiplex immunoassays for the detection of autoantibodies involved in connective tissue disease using clinically defined sera. Usefulness of the immunoassays will be defined by correlation to disease state. Using the immunoassays from Inova Diagnostics, Biomedical Diagnostics (BMD), and AtheNA, reactivity, to Smith (Sm), ribonucleic protein (RNP), SSA (Ro), SSB (La), Scl-70, and dsDNA or chromatin, we tested 273 clinically defined sera consisting of 57 systemic lupus erythrematosus (SLE) sera, 69 rheumatoid arthritis (RA) sera, 47 sera defined as various other connective tissue diseases, and 100 normal donor sera.