Value of the Widal test in the diagnosis of typhoid fever in an endemic area and suggestions for a modification. A preliminary study.

The Widal test for detection of typhoid fever was introduced in two rural hospitals in Nigeria. Because of undetectably low O agglutination titers, 74 sera were sent overseas for further determination by means of passive haemagglutination with O 9, 12-antigen, Vi-antigen and slide agglutination with H-d antigen suspensions. This full test showed discrepancies with the normal Widal test i.e. a false negative Widal H agglutination in 6 out of 17 patients in West Nigeria and a false positive Widal H test in 28 out of 49 patients in Central Nigeria. The full test should be applicable in a small laboratory, but its value has yet to be established.