Evaluation of a Rapid Immunochromatographic Assay Kit for the Diagnosis of Salmonella Typhi Infection / 대한임상미생물학회지

ABSTRACT

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.