[A comparative study of the ELISA and IF methods for antinuclear antibody test]

A new ELISA method for antinuclear antibody(ANA) test was investigated for its clinical usefulness by comparison with a widely used IF method. Both methods used Hep 2 cells as a substrate. ELISA method showed good reproducibility in both within-run(CV = 5.1 approximately 8.7%) and between-run(CV = 8.1 approximately 9.6%) assays. ROC analysis revealed that ELISA method had a higher sensitivity and an equal specificity as compared to IF method. Application of an auto analyzing system to ELISA method could induce the improvement of efficacy and labor saving. The coincidence rate between ELISA and IF methods was 78.6% on the samples from 887 patients with various disorders. In patients with drug induced lupus or connective tissue diseases except for rheumatoid arthritis, the discrepancies were caused mainly by the higher sensitivity of ELISA method. However, the ELISA test was less sensitive for the ANAs showing granular, nuclear membrane, or anti-PCNA antibody like staining patterns by IF method. In conclusion, ELISA method is useful for detecting ANAs because of its high sensitivity and efficiency, though it still has some points to be improved.