Summary and Explanation of the Typhoid Test

Typhoid fever is caused by S. typhi, a Gram-negative bacterium. World-wide an estimated 17 million cases and 600,000 associated deaths occur annually1. Patients who are infected with HIV are at significantly increased risk of clinical infection with S. typhi2. Evidence of H. pylori infection also presents an increase risk of acquiring typhoid fever. 1-5% of patients become chronic carrier harboring S. typhi in the gallbladder.

The clinical diagnosis of typhoid fever depends on the isolation of S. typhi from blood, bone marrow or a specific anatomic lesion. In the facilities that can not afford to perform this complicated and time-consuming procedure, Filix-Widal test is used to facilitate the diagnosis. However, many limitations lead to difficulties in the interpretation of the Widal test3,4.

In contrast, the Typhoid IgG/IgM Rapid Test is a simple and rapid laboratory test. The test simultaneously detects and differentiates the IgG and the IgM antibodies to S. typhi specific antigen5 thus to aid in the determination of current or previous exposure to the S. typhi.