Multi-laboratory evaluation of a scrub typhus diagnostic kit.
Scrub typhus is a major cause of febrile illness throughout the Asia-Pacific region. It is commonly undiagnosed, partly because of the lack of a simple, reliable diagnostic test which can be used in clinical laboratories. The indirect immunoperoxidase technique, configured into a test kit, was provided to technicians who were trained in its use. They used the kit during a 2 year field trial in their respective clinical hospital laboratories throughout Malaysia. In an evaluation using 1,722 consecutive sera tested in those laboratories, the kit was found to have a median sensitivity for IgG detection of 0.85 (range 0.33-0.95), a median specificity of 0.94 (range 0.88-1.00), reproducibility of 0.86, and efficiency of 0.92 when compared to the reference laboratory. In a proficiency survey in which 10 laboratories received 3 coded test samples, all but 2 laboratories had results within 1 dilution of the reference laboratory in quantitating specific IgG, whereas 7 laboratories were within 1 dilution in quantitating IgM. The shelf life of the kit was at least 1 year at 4 degrees C.
Kelly
D J
DJ
U.S. Army Medical Research Unit, Institute for Medical Research, Kuala Lumpur, Malaysia.
Wong
P W
PW
Gan
E
E
Chye
C T
CT
Cowan
D
D
Lewis
G E
GE
D000907:Antibodies, Bacterial / Q000097:blood*; D005069:Evaluation Studies as Topic; D006801:Humans; D007124:Immunoenzyme Techniques / Q000592:standards*; D007074:Immunoglobulin G / Q000032:analysis; D007075:Immunoglobulin M / Q000032:analysis; D012285:Orientia tsutsugamushi / Q000276:immunology*; D011237:Predictive Value of Tests; D011309:Preservation, Biological; D011933:Reagent Kits, Diagnostic / Q000592:standards*; D015203:Reproducibility of Results; D012612:Scrub Typhus / Q000175:diagnosis*
D000907:Antibodies, Bacterial; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D011933:Reagent Kits, Diagnostic