LEPTO DIPSTICK, A DIPSTICK ASSAY FOR DETECTION OF LEPTOSPIRA-SPECIFICIMMUNOGLOBULIN-M ANTIBODIES IN HUMAN SERA

We studied a dipstick assay for the detection of Leptospira-specific i mmunoglobulin M (IgM) antibodies in human serum samples. A high degree of concordance was observed between the results of the dipstick assay and an IgM enzyme-linked immunosorbent assay (ELISA), Application of the dipstick assay for the detection of acute leptospirosis enabled th e accurate identification, early in the disease, of a high proportion of the cases of leptospirosis. Analysis of a second serum sample is re commended, in order to determine seroconversion or increased staining intensity. All serum samples from the patients who were confirmed to b e positive for leptospirosis by either a positive microscopic agglutin ation test or a positive culture but were found to be negative by the dipstick assay were also judged to be negative by the IgM ELISA or rev ealed borderline titers by the IgM ELISA. Some cross-reactivity was ob served for sera from patients with diseases other than leptospirosis, and this should be taken into account in the interpretation of test re sults. The dipstick assay is easy to perform, can be performed quickly , and requires no electricity or special equipment, and the assay comp onents, a dipstick and a staining reagent, can be stored for a prolong ed period without a loss of reactivity, even at elevated temperatures.