A Comparative Study of Diazo Test and Blood Culture in Children With Clinically Compatible Typhoid Fever

Introduction: Typhoid fever causes a clinically indistinguishable disease with a wide range of clinical severity. This study was done to compare the Diazo test with blood culture. Methods: A cross-sectional comparative study was done for one year with a sample size of 100 children up to the age of 15 years in the Department of Paediatrics, Sree Balaji Medical College and Hospital, Tamilnadu, India. Diazo test and blood culture were done in enrolled children who had clinical symptoms and signs suggestive of typhoid fever. Results: Blood culture-positive cases were 26% and diazo-positive cases were 34%. Out of 26 blood culture-positive cases, 19 cases showed positive results and seven had a negative result by Diazo test and this was statistically significant. Diazo test had sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive predictive value, negative predictive value of 73.08%, 79.73%, 3.61, 0.34, 55.8%, 89.4% respectively. The measure of agreement Kappa value was found to be 0.480 which is considered to be a significant moderate agreement between the Diazo test and blood culture. Conclusions: Diazo test is a simple bedside test with a comparable degree of sensitivity and specificity and can be utilized for the diagnosis of typhoid fever in children in areas of scarce resources and thereby reducing the complications. Key words: Diazo test; Sensitivity; Specificity