Diagnostic Accuracy of Rapid Antibody Detection Test for Scrub Typhus.

OBJECTIVE

To detect the diagnostic accuracy of rapid antibody detection test using IgM immunochromatography for scrub typhus in children.

METHODS

This cross-sectional study enrolled children aged 2 months-18 years hospitalized over a period of 18 months with undifferentiated fever of duration five days or more. The blood samples were subjected to serological tests like Weil-Felix, Scrub IgM ELISA, immunofluroscence assay (IFA) and rapid diagnostic test (IgM Immunochromatography). Diagnostic accuracy was measured against IFA as the gold standard.

RESULTS

A total of 90 children were included in the study, among which 43 children were positive for gold standard test IFA. Rapid diagnostic test showed sensitivity of 88.3%, specificity of 89.3%, positive predictive value of 88.3% and negative predictive value of 89.3%. The sensitivity, specificity, PPV and NPV of Weil-Felix test was 39.5%, 84.2%, 58.6 and 71.1%, respectively and of IgM ELISA was 93%, 89.3%,88.8% and 93.3%, respectively.

CONCLUSION

IgM immunochromatography had good diagnostic accuracy for scrub typhus in children with acute undifferentiated fever.