Evaluation of serological diagnostic tests for Leptospirosis-A retrospective study

Abstract

Introduction

Leptospirosis is an emerging zoonotic bacterial infection that remains a major public health problem in tropical and

subtropical regions majorly in coastal regions ofIndia. Laboratory diagnosis of leptospirosis is mandatory because

of varied clinical picture and existence of similar infections in endemic regions which cause confusion in the

diagnosis. We evaluated and analyzed two immunodiagnostic test, Leptocheck WB-Rapid

immunochromatography test and Leptospira IgM ELISA (Panbio) test detecting Ig M antibodies (Ab) for Leptospira

in serum and compared with MAT (Microscopic agglutination test) test.

Materials and Methods

Blood samples from suspected patients of leptospirosis were tested by ELISA and Rapid test for IgM Ab detection

and MAT test from January 2022 to December 2023. The data were entered in Microsoft Excel and analyzed using

Epi Info software version 3.5.1. Descriptive analysis based on bivariant and multi-variant analysis was done. Chi

square test was applied and p-value found to demonstrate association between the tests.

Results

Out of 75 blood samples tested, 29 were positive by three different serological tests. ELISA and rapid test on

comparison with MAT showed 96.29%, 85.18% of sensitivity respectively and 93.75% of specificity. Predominant

serovar identified from MAT were L.Automonalis (77%) L. Australis (77%). Conclusion: This study suggests that

diagnostic accuracy of IgM ELISA for leptospirosis is sensitive in acute stage of the thedisease. Immunodiagnostic

methods are simple and easy to perform in detecting IgM antibody in acute phase compared to MAT in resource

limited settings.