Usefulness of the Widal test in diagnosing childhood typhoid fever in endemic areas

Abstract

Data are presented for 2382 children investigated for fever in a Malaysian hospital between 1984 and 1987 when Widal tests and blood cultures were a routine part of every fever screen. There were 145 children who were culture positive (TYP-CP) for Salmonella typhi, while 166 were culture negative but were diagnosed as having typhoid (TYP-CN). Analyses of the sensitivity and specificity of combinations of initial Widal titres in predicting a positive S. typhi culture in a febrile child (culture positive vs the rest) showed the best model to be an O- and/or H-titre of > or = 1 in 40 (sensitivity 89%; specificity 89%). While the negative predictive value of the model was high (99.2%) the positive predictive value remained below 50% even for very high titres of O and H (> 1 in 640), at which point the specificity was 98.5%, supporting the clinical view that a high proportion of the TYP-CN patients really were typhoid but were missed by culture. The TYP-CN patients showed a very similar clinical and age profile to TYP-CP patients. The length of history of fever did not affect the initial Widal titre in culture positive cases. The Widal test in children remains a sensitive and specific 'fever screen' for typhoid although it will not identify all cases. In children, lower cut-off points for O- and H-titres should be used than are generally recommended.

Rapid serologic diagnosis of pediatric typhoid fever in an endemic area: a prospective comparative evaluation of two dot-enzyme immunoassays and the Widal test.

“…In contrast to findings from other parts of Asia, [19][20][21][22] our data support the contention that the Widal test has poor diagnostic value in children with typhoid fever. 23,24 Most of the children presented in the second week of their illness and we used a cut-off titer of 1:80.…”

Typhoid fever in children in Africa

“…Six reported blood culture data from populations in whom minimal or no selection criteria were applied (included in this group are studies with no selection criteria for children aged <5 years but minimal criteria for those aged ≥5 years), four studies reported data from selected populations and two were case‐series. Among studies which considered the unselected group, only 2/6 report prevalences >1%, with 5.51% prevalence in Dhaka, Bangladesh and 6.1% in Malaysia (Choo et al. 1993; Sinha et al.…”

Evaluation of the Widal tube agglutination test for the diagnosis of typhoid fever among children admitted to a rural hdospital in Tanzania and a comparison with previous studies

“…Choo et al [21]. considered all febrile cases with an S.typhi negative blood culture as the control group which is problematic as a number of blood culture-negative results are likely to be false-negative due to the poor sensitivity of the blood culture [17-19,22]. Furthermore, it is difficult to compare the different test kits, as varying antigens perform differently [23].…”