Comparison of a rapid commercial test, Enterocheck WB^®, with automated blood culture for diagnosis of typhoid fever

Abstract

Background: Rapid diagnosis of typhoid fever is very important in the timely initiation of therapy.

Objectives: To evaluate the sensitivity and specificity of the Enterocheck WB^® test.

Methods: In a prospective study, the sensitivity and specificity of Enterocheck WB^® that detects IgM antibodies to Salmonella typhi were compared with blood culture using BacT/Alert.

Results: Four hundred and fifty patients with suspected typhoid fever were assessed both by blood culture and Enterocheck WB^®; 100 of them were either Enterocheck WB^®-positive or blood culture-positive or both for S. typhi. Both tests were positive in 47 of the 100 patients. In 45 patients, Enterocheck WB^® was positive but blood culture was negative. In eight cases, Enterocheck was negative but blood culture was positive. Using blood culture as the gold standard, the sensitivity of Enterocheck WB^® was 85·5%, specificity 88·6%, negative predictive value 97·7% and positive predictive value 51·1%.

Conclusion: The Enterocheck WB^® test can be performed at the bedside in 15 minutes and is a useful rapid method for diagnosis of typhoid fever.

Keywords:

• Typhoid fever
• Enterocheck WB®
• BacT/Alert
• diagnosis
• IgM
• Salmonella typhi
• children

We wish to thank the technicians of the Microbiology Laboratory for their contribution. We also thank Mr Sivam Sakthivel for assistance with the statistics.