Evaluation of clinical criteria for the diagnosis of leptospirosis.

Leptospirosis has a wide range of clinical presentation and therefore, clinical suspicion of the infection is often difficult. The objective of this study is to find out the usefulness of the clinical and epidemiological criteria in the diagnosis of leptospirosis and its comparison with microagglutination test (MAT).A total of 118 patients with undiagnosed fever of more than seven days duration were included in the study. Their clinical presentation was scored on the basis of a clinical criteria. Sera of the patients were tested for antibodies against leptospira with the help of microagglutination test using a battery of antigens. The usefulness of the criteria was evaluated and compared with microagglutination test.A total of 44 out of 118 (37.28%) patients could be provisionally diagnosed as cases of leptospirosis on the basis of the clinical criteria. Eighteen of these 44 (40.9%) patients had serological evidence of leptospirosis. The criteria had a sensitivity of 81.81%, specificity of 72.91%, a positive predictive value of 40.9% and a negative predictive value of 94.59% when compared with microagglutination test.The criteria had a moderate sensitivity and specificity. Considering the non-specific signs and symptoms of this infection, the positive predictive value is significantly high. The criteria has a high negative predictive value and this would help the clinicians exclude the diagnosis of leptospirosis with precision.