Enzyme linked immunosorbent assay compared to conventional methods in diagnosis of typhoid fever

The value of the Enzyme Linked Immunosorbent Assay [ELISA] in serodiagnosis of typhoid fever was assessed with a collection of sera from 110 feverish patients bacteriologically proven to have typhoid fever [74 acute and convalescent samples]. 15 cases were negative by both ELISA and Widal test. High titers of antibodies were found by ELISA [against O and H s.typhi antigenic components]. The sensitivity of ELISA was 86.4% whereas that of widal test was 70.2% for O agglutination and 64.8% for H agglutination, in case of acute sera. In case of convalescent sera, both ELISA and Widal test had the same sensitivity 86.1%. ELISA was found to be economical reproducible as well as suitable for handling large number of sera. This study has provided an evidence that ELISA conserves as a good substitute for Widal test in the diagnosis of S.typhi infection