Evaluation of InBios Scrub Typhus Detect IgM Rapid Test in acute fever cases from Southwest and East India

Background & objectives: Scrub typhus is clinically undifferentiated from other aetiologies for acute febrile illness such as enteric fever, dengue, malaria, and leptospirosis. Rapid ELISA tests are being used as an alternative to immunofluorescence assay in tropical countries. Methods: In this study, we compared and evaluated commercially available InBios Scrub Typhus Detect IgM Rapid Test (USA) for diagnosing human scrub typhus infection using archived and prospectively collected samples against the reference standard, InBios Scrub Typhus Detect IgM ELISA (USA). Results: The data analysis of archived samples on rapid test revealed a moderate sensitivity of 53.92% and a specificity of 100%. Meanwhile, prospective serum samples demonstrated higher sensitivity and specificity of 96.4% and 94.6%, respectively. Interpretation & conclusion: The InBios Scrub Typhus Detect IgM rapid test can be a good point-of-care assay during surveillance, outbreak investigations, and case identification.