Interpretation of the Widal test in the diagnosis of typhoid fever in Bangladeshi children.

The value of a Widal test in diagnosing typhoid fever was assessed in children aged between 1 and 10 years in Bangladesh. The test was done on sera specimens from 300 healthy school children, 100 patients with non-typhoidal febrile illness and 150 bacteriologically proven cases of typhoid fever. Salmonella typhi O and H agglutinin titres > 1:80 and > 1:160 were considered to be significant with 88% sensitivity and 98% specificity, respectively. Among the bacteriologically proven cases, 11.3% showed no response to either agglutinin, and in another 17.3% of cases there was no response for TO agglutinin. This study suggests that in children in an endemic area a positive Widal test is of considerable importance in diagnosing typhoid fever. Furthermore, negative results should be interpreted with caution and both the agglutinins must be considered equally important. Reliance on somatic (TO) antigen only will result in missed diagnosis.