Comparative study of Widal test to stool culture for the diagnosis of suspected typhoid fever: a study in a primary health centre, Ghana

Abstract

Background: Misdiagnosis of typhoid fever is common since most primary healthcare relies on only the Widal test without further confirmation. This study compared stool culture to the performance of the Widal test at the Methodist Hospital, Wenchi, in the Bono Region of Ghana. Methods: This study recruited 178 persons suspected of typhoid fever. Venous blood and stool samples were collected to assess antibodies to the Salmonella typhi (S. typhi) H and O antigens using the Ozotex Widal test kit and isolate S. typhi using culture techniques. An antibody titre value ≥ 1:80 was considered positive for the Widal test. Also, the performance of the Widal test was evaluated using the results from the stool culture as the standard reference. Results: The prevalence of typhoid fever, as confirmed by isolating S. typhi from the stool, was 6.2%. From the Widal test, the prevalence of typhoid fever was 71.3%, with 81.8% sensitivity, 29.3% specificity, 7.1% positive predictive value and 96.1% negative predictive value. Also, the Widal test has a lower agreement with the stool culture (kappa = 0.021). Conclusion: The Widal test was not dependable for diagnosing typhoid fever; hence, microbial culture should always confirm results from the Widal test.

Keywords

• typhoid fever
• widal test
• stool culture
• sensitivity
• healthcare