Browsing by Author "Wickramasinghe, S.A."

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    Evaluation of two immunodiagnostic tests for early rapid diagnosis of leptospirosis in Sri Lanka: a preliminary study
    (BioMed Central, 2015) Eugene, E.J.; Handunnetti, S.M.; Wickramasinghe, S.A.; Kalugalage, T.L.; Rodrigo, C.; Wickremesinghe, H.; Dikmadugoda, N.; Somaratne, P.; de Silva, H.J.; Rajapakse, S.
    BACKGROUND: Leptospirosis is often treated based on clinical diagnosis. There is a need for rapid laboratory diagnosis for this condition. The aim of this study was to compare the diagnostic accuracy of two rapid IgM based immunodiagnostic assays with the microscopic agglutination test (MAT), in acute leptospirosis infection. METHODS: MAT, IgM based immunochromatographic test (Leptocheck-WB) and IgM ELISA were performed using acute sera of patients clinically suspected to have leptospirosis (n = 83). Bayesian latent class modeling was used to compare the accuracy of these tests. RESULTS: Percentage positivity for MAT, Leptocheck-WB, and IgM ELISA were 48.1, 55.3, and 45.7 % respectively. Bayesian latent class modeling showed a combined positivity rate of leptospirosis of 44.7 %. The sensitivity of MAT, Leptocheck-WB and IgM ELISA were 91.4, 95 and 81.1 %, and specificity were 86.7, 76.4 and 83.1 %, respectively. CONCLUSIONS: Leptocheck-WB has high sensitivity, and, because it is quick and easy to perform, would be a good screening test for acute leptospirosis infection. IgM ELISA has good specificity, and is comparable with MAT; given that it is easier to perform and more widely available than MAT, it would be a more appropriate confirmatory test for use in hospitals with limited access to a specialized laboratory.
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    A pilot study on comparison of rapid immunodiagnostics for confirmation of leptospirosis
    (Sri Lanka Medical Association, 2012) Eugene, E.J.; Wickramasinghe, S.A.; Kalugalage, T.L.; Rodrigo, C.; Wickremesinghe, H.; Dikmadugoda, N.; Somaratne, P.; de Silva, H.J.; Rajapakse, S.; Handunnetti, S.M.
    INTRODUCTION: In Sri Lanka, leptospirosis is mostly diagnosed on clinical grounds. Serological confirmation is not obtainable during the acute stage of the illness. There is a need for rapid immunodiagnostics for confirmation of leptospirosis. Two immunodiagnostic assays, ie: enzyme linkedimmnnosorbent assay (ELISA) and immunochromatographic technique Leptocheck-WB test (LCT) areused to detect leptospira specific IgM antibodies which are prevalent in early stages of acute infections. AIMS: To compare the efficacy of these two rapid immunodiagnostic assays with the microscopic agglutination assay (MAT) to determine their applicability. Methods: A set of sera (n=83) collected in 2010 for which MAT titres were available was used to perform IgMELISAandLCT. RESULTS: Positivity for LCT and IgM ELISA were 55.4% and 48.2% respectively, and both assays detected acute infection by day 3 of the illness. MAT> 400 was used as the reference standard. For LCT, the overall sensitivity, specificity, accuracy, PPV and NPV (86.5%, 75.0%, 79.6%, 69.6% and 89.4% respectively) were higher compared to the respective values for IgM ELISA (50.0%, 62.3%, 57.1%, 50.0%, 62.3%). The highest of these values were observed during the first week for LCT and during the second week for IgM ELISA. The highest agreement was observed between LCT and MAT>400 (p=0.568) and there was a good agreement between LCT and IgM ELISA (p=0.520). CONCLUSIONS: The high sensitivity and specificity, ease of use, and non-requirement of specialized skills and equipment makes LCT a good choice for screening, while IgM ELISA is an appropriate test for confirming acute leptopsirosis.