comparison of two elisa methods for the laboratory diagnosis of acute leptospirosis

background: leptospirosis is the most common zoonosis widespread in tropical and temperate countries with low social-economic status. we aimed to compare an elisa kit with an in-house elisa assay to test the serum samples of the patients who were suspicious of leptospirosis according to their clinical symptoms.   methods: a total of 282 serum samples of patients suspicious of leptospirosis admitted to hospitals in rasht city (north of iran) were examined for sero-diagnosis of leptospirosis. blood samples were obtained with mean time of 6.36 days after the onset of the symptoms. antibodies were detected using a commercial qualitative and by an in-house semi quantitative igm and igg elisa and the results were compared with microscopic agglutination test (mat) as the gold standard. all specimens with titers ≥320 against a pathogenic serovar in mat were considered positive for leptospirosis.   results: the results of mat have demonstrated that 70 serum samples (24.8%) had a positive reaction with one of the leptospira serovar. the sensitivity, specificity, positive and negative predictive values were 87.1% , 91.0 %, 67.8%, and 95.5% for in-house elisa assay, respectively, and 100%, 42.9%, 36.6%, and 100 % for commercial igm elisa assay, respectively.   conclusion: our results showed that igm elisa assay is a reliable and sensitive method for the laboratory diagnosis of acute leptospirosis. in-house semi quantitative igm elisa was more specific and commercial igm elisa was more sensitive.