The Scrub Typhus IgM Rapid Test is a qualitative, membrane-based immunoassay for the detection of IgM. The membrane is pre-coated with a mixture of novel recombinants (representing several geographical isolates; 2, 3) on the test line region and appropriate control antigen on the control line region. During testing, the sample reacts with the dye conjugate (anti-human IgM colloidal gold conjugate) which has been pre-coated in the test device. The mixture then migrates upward on the membrane chromatographically by capillary action to react with ST derived recombinant antigens on the membrane and generates a red line. Presence of this red line indicates a positive result, while its absence indicates a negative result. Independent of the presence or absence of antibody to scrub typhus antigens, a red line at the control line region will always appear when the sera-gold migrates to the immobilized control region. The presence of this red line verifies for sufficient sample volume and proper flow of reagents.