Diagnosis of Leptospirosis: Comparison between Microscopic Agglutination Test, IgM-ELISA and IgM Rapid Immunochromatography Test

Abstract

BackgroundLeptospirosis is diagnosed on clinical grounds, and confirmed by microscopic agglutination test (MAT). IgM-ELISA (Serion-Virion) and immunochromatography test (Leptocheck-WB) are two immunodiagnostic assays for leptospirosis. Their sensitivity, specificity and applicability in Sri Lanka have not been systematically evaluated.MethodsClinically diagnosed leptospirosis patients (n = 919) were recruited from three hospitals in the Western Province of Sri Lanka, during June 2012 to December 2013. MAT, IgM-ELISA and Leptocheck-WB were performed on all patient sera. MAT titer of ≥400 in single sample, four-fold rise or seroconversion ≥100 in paired samples were considered as positive for MAT. For diagnostic confirmation, MAT was performed during both acute and convalescent phases. Anti-leptospiral IgM ≥20 IU/ml and appearance of a band in the test window were considered as positive for IgM-ELISA and Leptocheck-WB test respectively. Patients with an alternative diagnosis (n = 31) were excluded. Data analysis was performed using two methods, i) considering MAT as reference standard and ii) using Bayesian latent class model analysis (BLCM) which considers each test as imperfect.ResultsMAT, IgM-ELISA and Leptocheck-WB positivity were 39.8%, 45.8% and 38.7% respectively during the acute phase. Acute-phase MAT had specificity and sensitivity of 95.7% and 55.3% respectively, when compared to overall MAT positivity. IgM-ELISA and Leptocheck-WB had similar diagnostic sensitivity when compared with acute-phase MAT as the gold standard, although IgM-ELISA showed higher specificity (84.5%) than Leptocheck-WB (73.3%). BLCM analysis showed that IgM-ELISA and Leptocheck-WB had similar sensitivities (86.0% and 87.4%), while acute-phase MAT had the lowest sensitivity (77.4%). However, acute-phase MAT had high specificity (97.6%), while IgM-ELISA and Leptocheck-WB showed similar but lower specificity (84.5% and 82.9%).ConclusionsBoth IgM-ELISA and Leptocheck-WB shows similar sensitivities and specificities. IgM-ELISA may be superior to MAT during the acute phase and suitable for early diagnosis of leptospirosis. Leptocheck-WB is suitable as a rapid immunodiagnostic screening test for resource limited settings.

A Leptospirosis Workup by Evaluation of Efficiency of Two Rapid Immunodiagnostic Tests in Comparison with Microscopic Agglutination Test

“…Many published data cited PanBio ELISA to be highly sensitivity in early stages of infection which was in agreement with our study (Panwala et al, 2011;Niloofa, 2015 andZochowski et al, 2001). Certain studies reported a lower rate of sensitivity and specificity (Blacksell et al, 2006 andDesakorn et al, 2012).…”

“…Our study recorded a sensitivity of 75% and specificity of 95% with admission sample for Leptocheck WB in comparison with the reported data (Goris et al, 2013). But some of the earlier reports showed a higher sensitivity and lower specificity rate (Panwala et al, 2011;Panwala Tanvi et al, 2015 andNiloofa et al, 2015).This would be due to geographical distribution of leptospira serovars and time of blood collection.…”

Prevalencia de anticuerpos anti-Leptospira spp. en personas con exposición laboral en el departamento del Tolima

“…se realizó mediante la prueba de elisa debido a que esta técnica es sencilla y fácil de ejecutar en condiciones de infraestructura mínima y como una estrategia de tamizaje preliminar de bajo costo. Por otro lado, la complejidad de la prueba mat requiere de un número considerable de serovares y su mantenimiento y la ausencia de laboratorios especializados en la región imposibilitan su uso de rutina y tamizaje [29][30]. Recientemente se están desarrollando estudios para la caracterización molecular de serotipos de aislamientos en Colombia, para establecer un panel diagnóstico más adecuado al contexto epidemiológico del país [31,32].…”

“…La técnica de elisa usada para la detección de anticuerpos IgM contra Leptospira spp. es un método convencional ampliamente usado en el diagnóstico de leptospirosis, por lo tanto, estudios que compararon mat y elisa evidenciaron resultados semejantes en cuanto a su sensibilidad y especificidad [29,30], siendo elisa una prueba de referencia [16]. Los resultados de este estudio indican la presencia de anticuerpos contra Leptospira spp, pero no confirman la infección y, por lo tanto, no constituye evidencia suficiente para emitir un diagnóstico de leptospirosis.…”

A Review of Laboratory Diagnosis and Treatment of Leptospirosis

“…Usually, the saprophytic strain L. biflexa which shares several surface antigens with pathogenic strains and pathogenic species have also been used [34,44]. The specificity and the sensitivity of these Elisa are quite variable.…”