Evaluation of the immunochromatographic (Leptocheck) test for detection of specific antibodies against leptospires.

BACKGROUND: Leptospirosis is a febrile worldwide zoonosis. Routine diagnosis of leptospiral infection is based on demonstration of specific antibodies with serological tests. Performance of the reference serological test, the microscopic agglutination test (MAT), requires significant expertise. The aim of our study was to find out if leptospiral infection can be proven with simple, rapid, commercially available immunochromatographic Leptocheck test in order to introduce it for the first level diagnosis in emergency cases with less specialized laboratory staff. METHODS: In all, 590 serum samples of patients with clinical manifestations suggestive of leptospirosis were collected and tested with MAT and Leptocheck test. For confirmation of the results some other diagnostic methods such as polymerase chain reaction (PCR) and Leptospira isolation were performed. RESULTS: Results of both serological tests were consistent in 576/590 (97.63%) cases but Leptocheck gave more positive results in comparison to MAT (36 and 12, respectively) at first patient's testing. Following up the patient, MAT became positive in majority of Leptocheck positive patients at first visit. Leptospiral DNA was detected in nine blood and six urine samples belonging to thirteen different patients while only two samples were culture positive. CONCLUSION: In comparison with serological tests, PCR and culture have low sensitivity. According to our findings we conclude that Leptocheck test can prove leptospiral infection and could be used for rapid diagnosis of leptospirosis, later the sample should be confirmed with MAT.