Laboratory diagnosis of typhoid fever requires isolation and identification of Salmonella enterica serotype Typhi. In many areas where this disease is endemic, laboratory capability is limited. We studied the value of the Widal tube and slide agglutination test for the diagnosis of typhoid fever. Blood donor controls were screened with a slide agglutination test for the Salmonella enterica serotype Typhi O and H antigens, and positives were then tested with the Widal test. We concluded that the majority tested (51%) had an H agglutinin titre of <1/20 with 2% having a titre of 1/160. For 0 agglutinins, 31% had a titre of 1/80 and 2% had a titre of 1/160 that O and H agglutinin titers of >1/200 is of diagnostic significance. Out of 10 samples subjected to 2-mercapto-ethanol test 4 showed reductions indicating the presence of IgM antibodies and 6 sera negative for the test. Widal test can be of diagnostic value in the early stage of disease and thus help in reducing morbidity and mortality from typhoid. A false-positive may be the result of past infection with serotype Typhi or another nontyphoidal Salmonella serotype that shares common antigens.
