Prospective Evaluation of a Rapid Diagnostic Test Dot EIA (Typhidot) for Typhoid Fever

Objective: A prospective evaluation of a rapid diagnostic test Dot EIA (Typhidot) for typhoidfever. Study design & duration: This prospective study was undertaken in a tertiary hospital from April2007 to July 2008. Research Methodology: The patients were divided into three groups as I, II & III with typhoidfever, typhoid suspects & non-typhoid febrile illnesses respectively. Blood culture and typhidottests were done for the subjects included in the study. The validity of the typhidot test was evaluatedby determining the sensitivity, specificity, positive and negative predictive value. Results: The mean age in years was 28±19 (SD). Out of 150 subjects, males were more thanfemales. The typhidot IgM yielded very high sensitivity, specificity and a negative predictive valuenoted in group I = 93% & 98.80% 93% respectively and in group II= 79%, 98.80%, & 83%respectively where as in group III (non-typhoid febrile controls), the IgM antibodies were notdetected at all (p=0.01). Sensitivity, specificity, and negative predictive value for typhidot IgGnoted in group I = 73%, 63%, & 22.4% respectively and in group II = 82%, 37%, & 68% respectively(p=0.03) and a false positive reading of 63% was noted in group III (controls). Conclusions: Typhidot test is a valid tool in the diagnosis of typhoid fever but a reliable and validinterpretation should be based on positive IgM.