Clinical value of Tubex and Typhidot rapid diagnostic tests for typhoid fever in an urban community clinic in Bangladesh

Abstract

Tubex and Typhidot, rapid tests for typhoid fever, performed well in evaluations conducted in hospital settings among patients with culture-confirmed typhoid fever. We evaluated these tests in a community clinic in Bangladesh. Blood samples were obtained from 867 febrile patients for culture, Typhidot and Tubex tests. Considering the 43 blood culture-confirmed cases of typhoid fever as typhoid positive and the 24 other confirmed bacteremia cases as typhoid negative, Tubex was 60% sensitive and 58% specific, with 90% positive and 58% negative predictive values (NPVs); Typhidot was 67% sensitive and 54% specific, with 85% positive and 81% NPVs. When blood culture-negative patients and other bacteremia cases together were considered typhoid negative, positive predictive values were only 14% for Tubex and 13% for Typhidot, increasing to only 38% and 20% when restricted to patients with > or = 7 days of fever. We conclude that the value of Tubex and Typhidot tests for typhoid fever diagnosis in a community clinic in urban Bangladesh is low.