Two methods for rapid serological diagnosis of acute leptospirosis.
Leptospirosis is a common and underdiagnosed zoonosis. Two rapid assays for serological diagnosis of acute leptospirosis in diagnostic laboratories, the immunoglobulin M (IgM)-dipstick assay and the indirect hemagglutination assay (IHA), were evaluated and compared with standard assays. Sera were examined from 104 patients admitted to a hospital for investigation in a leptospirosis diagnostic protocol. Specimens for serology were taken on days 1 and 4 of the patients' hospital stay. Antibodies were detected using an IgM-enzyme-linked immunosorbent assay (ELISA), microscopic agglutination test (MAT), an IgM-dipstick assay, and an IHA. Fifty-one patients were found to have leptospirosis. The sensitivity of the IgM-dipstick assay was 98%, its specificity was 90.6%, its positive predictive value was 90.9%, and its negative predictive value was 98%. The sensitivity of the IHA was 92.2%, its specificity was 94.4%, its positive predictive value was 95.9%, and its negative predictive value was 92.7%. The standard IgM-ELISA and MAT, were positive in the first samples tested from 67 and 55% of the cases, respectively, and the rapid IgM-dipstick assay and IHA were positive in 71 and 49%, respectively, in the first sample tested. Both rapid assays are highly sensitive and specific. Neither requires specialized equipment, and both are suitable for use in diagnostic laboratories.
Levett
P N
PN
School of Clinical Medicine & Research, University of the West Indies, Bridgetown, Barbados. levett@sunbeach.net
Branch
S L
SL
Whittington
C U
CU
Edwards
C N
CN
Paxton
H
H
D000208:Acute Disease; D004797:Enzyme-Linked Immunosorbent Assay; D006386:Hemagglutination Tests / Q000592:standards*; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D007922:Leptospirosis / Q000175:diagnosis* / Q000276:immunology; D011237:Predictive Value of Tests; D011934:Reagent Strips / Q000592:standards*; D012680:Sensitivity and Specificity
D007075:Immunoglobulin M; D011934:Reagent Strips