Background: Widal test, whose sensitivity and specificity are variable from region to region depending on the incidence of typhoid fever, is still in use and shows a relatively low positive predictive value in Korea. We evaluated a rapid immunochromatographic assay (ICA) kit for the rapid diagnosis of Salmonella Typhi infection.

Methods: Twenty five patients with Salmonella Typhi bacteremia were selected for the patient group. For the control group, 21 nontyphoidal salmonellosis patients, 56 non-Salmonella bacteremia patients, and 57 healthy individuals were selected for evaluating the specificity of ICA test. Each serum specimen was tested with the SD Salmonella Typhi IgG/IgM kits (Standard Diagnostics, Inc., Yongin, Korea).

Results: The ICA showed a sensitivity of 100% in Salmonella Typhi patients, and specificities of 61.9%, 82.1% and 91.2% in nontyphoidal salmonellosis patients, non-Salmonella bacteremia patients, and healthy individuals, respectively. The ICA test showed a high sensitivity but a low specificity when compared with the Widal test.

Conclusion: The ICA test by SD Salmonella Typhi IgG/IgM kit is highly sensitive, but its specificity is relatively low. The ICA test is simple, objective, and suitable for screening typhoid fever. (Korean J Clin Microbiol 2007;10:123-127)