Diagnostic utility of an immunochromatography test for the detection of Leptospira IgM antibodies in domestic dogs

A cross-sectional study using 99 serum samples of dogs from southern Chile was conducted to determine the diagnostic utility of a rapid immunochromatography assay for the detection of Leptospira specific IgM antibodies as screening test and as a potential aid in the diagnosis of leptospirosis in animals with and without clinical suspicion of the disease. The Microscopic Agglutination Test (MAT) was used as reference assay. Anti-Leptospira antibodies were detected in 37.3% of the dogs with MAT. Using the immunochromatography test, specific IgM antibodies were found in 13.1% of sampled dogs. The sensitivity of the rapid test as screening assay was 29.7% (95% Confidence Interval=16.4-47.2) and the specificity was 96.7% (95% Confidence Interval=87.8-99.4). 40.0% of the canines with clinical suspicion of leptospirosis and 37.1% of dogs without clinical signs were serological reactors to MAT, but none of MAT reactive dogs with clinical suspicion tested positive in the rapid test. Rapid and user-friendly diagnostic procedures for canine leptospirosis such as this immunochromatography assay could be important tools to use in clinical practice, however, further studies are needed to obtain more information about their utility, considering that diagnostic tests could not have similar performances in different geographic locations, clinical and epidemiological contexts.