Evaluation of the Widal test for the diagnosis of typhoid fever in Lebanon

Typhoid fever is a major public health problem in developing countries. In Lebanon, where the sanitary infrastructure was severely damaged during the civil war, the high prevalence of typhoid fever creates a pressing need for a rapid and reliable diagnostic tool. To evaluate the diagnostic usefulness of the Widal test, patients with a positive blood culture for Salmonella typhi (n=78) were compared to controls with fever due to another infection (n=65) and with blood donors (n=96). Discrimination between the patient group and the two control groups was best when an agglutinin O titer of 1/160 or more was used. With this cutoff, sensitivity was 67.9%; specificity was 93.8% versus the febrile controls and 100% versus the blood donors. These results suggest that despite its well-known limitations the Widal test remains a valuable tool for typhoid fever control in many developing countries.