Comparative evaluation of serological tests in diagnosis of kala azar.

Four serological tests, viz., counter immunoelectrophoresis (CIEP), indirect fluorescent antibody (IFA) test, enzyme linked immunosorbent assay (ELISA) and dot-enzyme linked immunosorbent assay (dot-ELISA) were compared for their sensitivity and specificity for diagnosis and epidemiological studies of kala azar. Sera from patients who were parasite positive (58), parasite negative (16), clinically diagnosed (53), treated (31) and from healthy controls (42) were tested for presence of antibodies by these techniques. Antibodies were detected in treated patients even after 18-24 months by ELISA (77.4%) and dot-ELISA (74.19%). In clinically diagnosed patients antibodies were present in 90.56 per cent by both the tests. The sensitivity and specificity of CIEP was 0.77 and 1.0, for IFA 0.87 and 0.95 respectively and for ELISA and dot-ELISA 0.92 and 0.9 respectively. Due to the requirement of small quantity of reagents and simplicity of the test, dot-ELISA is found to be more suitable for use in peripheral laboratories both for diagnosis and seroepidemiology.