DOI: 10.36347/sjams.2018.v06i04.019

Pages: 1481-1485

Antinuclear antibody testing is primarily applied as a diagnostic and prognostic tool for connective tissue disorders. Antinuclear antibodies can be detected by indirect immunofluorescence assay and enzyme immunoassay. This study was undertaken to compare the performances and cost effectiveness of immunofluorescence assay (IFA) using different substrates and enzyme immunoassay (EIA) in patient sera sent for routine testing of antinuclear antibodies.89 consecutive patient sera, clinically suspected to have connective tissue disorders, sent for routine antinuclear antibodies testing were analyzed by immunofluorescence assay using different substrates such as in-house mouse liver, BIOCHIP combination slide having mosaic HEp 20-10/ primate liver (Euroimmun) and EIA using BindazymeTM ANA kit MK 200. Among the 89 sera, the number of sera positive for antinuclear antibodies were 33(37%) by IFA-mouse liver, 28(32%) by IFA- HEp20-10, 34 (38%) by IFA- primate liver and 19(21%) by EIA. When IFA-HEp 20-10 was taken as the reference method, the sensitivities, specificities, positive & negative predictive value of the other methods were as follows: 71%, 79%, 61%, 86% for IFA-mouse liver and 46%,90%,68%,79% for EIA. Immunofluorescence assay with in-house mouse liver substrate gives comparable results with commercial slides and is cost effective. Commercially available combination slides have performed well on all aspects; however they are not cost effective. EIA kit alone cannot be used as a screening test for antinuclear antibodies.