Evaluation of latex agglutination test for diagnosis of leptospirosis using native strains

Background and Leptospirosis is a common zoonosis throughout the world and common in the flat area of Guilan, Iran, with seasonal incidence, especially in rice farmers. Clinical diagnosis of leptospirosis is difficult, because its symptoms are similar to several acute infective diseases. Serological assays are important in diagnosis of the disease and microscopic agglutination test (MAT) is a gold standard, however, it is not a routine test in diagnostic laboratories. Thus, a simple and reliable test is a necessity. In this study, we evaluated a latex agglutination test using native strains of leptospires. A number of 98 positive cases and 54 negative cases which were screened by MAT, along with 30 sera of other diseases as control samples, were examined by latex agglutination test, using an antigenic suspension (whole antigen), which was extracted from 4 common native strains. False positive and false negative rate were 15 and 12 consequently. Sensivity, specificity, positive predictive value, negative predictive value, and accuracy were 89.0%, 84.5%, 86.7%, 87.2%, and 87.0% respectively. Regarding the considerable rate of sensivity and specificity of the test which is compatible to other performed studies, in addition to the simple performance test, does not need a complex laboratory facility, which may also be carried out in rural regions, therefore, this test is valuable for primary screening.