A SYSTEMATIC EVALUATION OF RAPID DOT-EIA, BLOOD CULTURE AND WIDAL TEST IN THE DIAGNOSIS OF TYPHOID FEVER

Abstract

Abstract Background: Typhoid fever, caused by Salmonella enterica serotype Typhi, is endemic in the Indian sub-continent including Bangladesh, South-east and Far-east Asia, Africa and South Central America. The disease can occur in all age group with highest incidence among children. Blood culture is regarded as the gold standard for diagnosis and carry 70-75% diagnostic yield in the first week of illness. However, this requires laboratory equipment and technical training that are beyond the means of most primary health care facilities in the developing world. Typhidot is a rapid dot-enzyme immune assay (EIA), which detects IgG and IgM antibodies to a specific 50 kD outer membrane protein (OMP) antigen of Salmonella enterica serotype Typhi. Typhidot becomes positive as early as in the first week of fever. The results can be visually interpreted and is available within one hour. Materials and method: Fifty blood samples, collected aseptically from patients clinically diagnosed of Typhoid fever, were evaluated by blood culture, Widal test and Typhidot. Results: Of the 50 patients, 33 (66%) were positive by blood culture. Widal test was positive in 33(66%) patients which included 26 in blood culture positive patients and 7 in blood culture negative patients. Typhidot was positive in 37 (74%) patients. Thus, in comparison to the gold standard test i:e blood culture, Typhidot and Widal test had sensitivity and specificity of 100% & 76% and 78.78% & 58.82% respectively. Conclusion: Typhidot is found to have high sensitivity and good specificity and could be applied as a good alternate in resource poor nation. Further, it is simple to perform, reliable when compared to Widal test, and rapid, with results being available in one hour when compared to 48 hours for blood culture and 18 hours for Widal test.