Comparison of the Farr radioimmunoassay, 3 commercial enzyme immunoassays and Crithidia luciliae immunofluorescence test for diagnosis and activity assessment of systemic lupus erythematosus.

Backgrounds: Among anti-double-strand (ds)DNA antibody assays, Farr radioimmunoassay is decreasingly used because it requires radioactive material and is labor intensive. We evaluated the performance of Farr, three commercial enzyme immunoassays (EIAs) and the Crithidia luciliae immunofluorescence test (CLIFT) in systemic lupus erythematosus (SLE).

Methods: Anti-dsDNA antibodies were determined in 99 SLE patients, 101 healthy subjects, and 53 patients with autoimmune rheumatic diseases.