The Evaluation of ANA and dsDNA results in patient with suspected autoimmune disease

Antinuclear antibodies (ANA) and double-stranded DNA (dsDNA) antibodies are widely used for diagnosis of autoimmune disease. The aim of this study was to investigate the prevalence of ANA and anti-dsDNA in patient with suspected autoimmune disease. Serum samples were obtained from different clinics of Sakarya Educational and Research Hospital. Each of these serum samples was tested for the presence of ANA and anti-dsDNA by ELISA technique. These tests were performed by commercial kits according to the manufacturer's instructions. ANA and anti-dsDNA results were classified as positive or negative for each patient. Borderline results were arbitrarily classified as positive. In this study, ANA and anti-dsDNA were found positive 2.96% (58/1975) and 4.52% (29/642) respectively. There is no statistical significant correlation between ANA and anti-dsDNA positivity. Only two patient both ANA and anti-dsDNA were found positivity by ELISA kits. Agreement between assays is generally marginal. ELISA technique seems to be less sensitive than fluorescent tests for ANA with fewest positivity rates. These results may be due to a number of factors which may contribute to the variability on ELISA. Finally, each of the autoantibody assays provides different criteria for diagnosis, but ANA screen test should be followed up with fluorescent tests to provide proper diagnostic information.