Evaluation of typhidot [IgM] in early and rapid diagnosis of typhoid fever

ABSTRACT

Typhoid fever is widely recognized as a major public health problem in developing countries. A simple, reliable and rapid diagnostic test is needed for clinicians especially in areas where laboratory services are limited. To evaluate sensitivity and specificity of typhidot [IgM], a serological test to identify IgM antibodies against salmonella typhi. This was a prospective study. Northern Institute of Medical Sciences [NIMS] and Ayub Teaching Hospital Abbottabad. 1[st] November 2009 to 31[st] August 2010. A total of 100 patients with clinically suspected typhoid fever were studied and divided into three main groups as A, B and C, with definite typhoid fever, typhoid suspects plus non-typhoidal illnesses and healthy controls respectively. Blood culture and typhidot [IgM] tests were conducted for all subjects included in the study. The validity of typhidot [IgM] test has been evaluated by determining the sensitivity, specificity, positive and negative predictive values. In our study, majority [75%] were males and [25%] females with M to F ratio of 31. The mean age of study group was 26.31 +/- 11.8 [SD] years. Among 100 clinically diagnosed typhoid fever patients, 19 had positive blood culture for S.typhi and 71 were typhidot [IgM] positive. Out of 19 culture positive patients, 18 [94.73%] were true typhidot [IgM] positive, which was also falsely positive in 05 [20.83%] among 24 non- typhoidal febrile controls. None of the healthy controls was positive for typhoid [IgM] test. The sensitivity, specificity, negative and positive predictive values of typhidot [IgM] test using blood culture as gold standard were 94.73%, 90%, 97.72% and 78.26% respectively for patients having typhoid fever. Typhidot [IgM] test is a simple, reliable, rapid and valid diagnostic tool for typhoid fever especially in areas where laboratory services are limited