Fluorescent antinuclear antibody and anti-double-stranded DNA antibody testing: a four years experience.

Fluorescent antinuclear antibody test (FANA) and anti-double stranded deoxytribonucleic acid (dsDNA) antibody testing is an integral part of the evaluation of the patients who are suspected of having connective tissue disease. We tested 2,140 serum samples for FANA and 1,460 serum samples for anti-dsDNA antibodies. Of 2,140 serum samples tested for FANA, 492 (23%) yielded a positive result (titre of 1:80 or greater) and of 1,460 serum samples tested for anti-dsDNA, 69 (4.7%) yielded positive results. Highest number (n = 27) of serum samples positive for anti-dsDNA antibodies were found in serum samples that were positive for FANA test at a titre of 1:1280 or greater. In conclusion, FANA test can be used as an initial screening test for connective tissue/autoimmune disorders.