Evaluation of Diagnostic Significance and Cost Effectiveness of ELISA and IFA for the Diagnosis of Autoimmune Disorders

Abstract

Background: The presence of antinuclear antibodies (ANA) is a hallmark of autoimmune diseases. As Clinicopathological classification of autoimmune diseases is difficult without laboratory support, laboratory testing is of helps in diagnosis, treatment, prognosis, and prediction of the pathological changes by disease activity. Although different tests are available for ANA detection enzyme linked immunosorbent assay (ELISA) is the mainstay of diagnosis in most routine laboratories. Indirect immunofluorescence antinuclear antibody test (IFA) though currently the “gold standard” it is not widely practiced. Most studies have used Hep2 cells for the detection of autoantibodies by IFA. However Hep 2000 Ro is superior compared to Hep 2 which lacks capability of detecting some autoantibodies like Ro antibodies. Hence, this study was undertaken to compare the diagnostic value and cost effectiveness of ANA pattern, ELISA with profile testing for patients suspected to have autoimmune disorders. Results: In the present study we observed high prevalence of autoimmune diseases in females (75.82%).ANA-ELISA in criteria matched cases with respect to ANA-IFA had a low sensitivity (59% versus 80%), higher specificity (84% versus 70%). Statistical analysis of ELISA and IFA with respect to ANA Profile showed a very less sensitivity by ELISA over IFA (51% vs. 78%) and equal specificity (70-72%) in 142 criteria matched cases. Conclusions: Statistically significant differences between ELISA and IFA infers IFA-ANA is a very appropriate method for screening purposes also IFA have capability of finding anti-mitochondrial and other cytoplasmic antibodies, which is not possible with ELISA.