Evaluation of enzyme-linked immunosorbent assay and indirect hemagglutination assay for detection of leptospiral antibody by using three different antigens.

ABSTRACT

Evaluation of enzyme linked immunosorbent assay (ELISA) and indirect hemagglutination assay (IHA) for detection of leptospiral antibody were performed using three different soluble antigens extracted from Leptospira interrogans serovar Bataviae including heat extracted antigen (HEA), sonicated antigen (SA) and deoxycholate extracted antigen (DEA). One hundred seventy-eight sera from 85 confirmed leptospirosis cases and 202 non-leptospirosis cases were examined SA-IHA showed the highest sensitivity of 98.8% followed by SA-ELISA-IgM and DEA-ELISA-IgM which showed an equal sensitivity of 97.6%. SA-ELISA-IgM was the most specific (96.5%) test followed by DEA-ELISA-IgM and SA-IHA which gave an equal specificity of 94.1%. The IgG-ELISA tests were less sensitive and specific than the others. These data indicated that the IgG-ELISA tests were not suitable as diagnostic tests for acute leptospirosis in humans. Using acute phase sera the sensitivity of DEA-ELISA-IgM, SA-ELISA-IgM and HEA-ELISA-IgM were 22.4%, 20.0% and 20.0% respectively, while those of the IgG ELISA tests were 32.9%, 17.6% and 10.6% respectively, the sensitivity of SA-IHA and DEA-IHA were 22.4% and 10.6% respectively. In conclusion, both the IgM-ELISA tests using SA and DEA and the IHA using SA are not different in diagnosis of human leptospirosis. SA is the most suitable antigen for detection of leptospiral antibody by IgM ELISA and IHA.