Limited Diagnostic Capacities of Two Commercial Assays for the Detection of Leptospira Immunoglobulin M Antibodies in Laos

Abstract

The diagnostic utility of immunochromatographic (Leptotek) and enzyme-linked immunosorbent assay (ELISA; Panbio) tests for the detection of Leptospira immunoglobulin M antibodies was assessed in febrile adults admitted in Vientiane, Laos. Both tests demonstrated poor diagnostic accuracy using admission serum (Leptotek sensitivity of 47.3% and specificity of 75.5%: ELISA sensitivity of 60.9% and specificity of 65.6%) compared to the Leptospira "gold standard" microscopic agglutination test.The laboratory diagnosis of acute Leptospira infection is usually dependent on serological methods. The "gold standard" microscopic agglutination test (MAT) requires paired specimens and considerable technical resources and training and is therefore not useful for acute patient management (5). Rapid methods, such as lateral flow immunochromatographic tests (ICT) and enzyme-linked immunosorbent assay (ELISA) formats that detect leptospiral immunoglobulin M (IgM) antibodies have demonstrated high diagnostic accuracy (1,4,8,10,11). However, a recent study in Viet Nam suggested a poor diagnostic utility of such tests there (9). Here we report the diagnostic accuracy of a commercial ELISA and an ICT for the detection of Leptospira IgM antibodies among adults with fever in the Lao People's Democratic Republic (Laos), where leptospirosis is endemic.Human sera were collected after informed oral consent was obtained as part of a study to determine the causes of unexplained fever for patients presenting at Mahosot Hospital, Vientiane, Laos, between November 2001 and October 2003 (7). Paired admission and convalescent-phase serum specimens were available from 186 patients (total sample, n ϭ 372) and stored at Ϫ85°C until tested. Unpaired sera were not included. Ethical approval was granted by the Ethical Review Committee of the Faculty of Medical Sciences, National University of Laos, Vientiane, Laos.A commercial ELISA (Panbio Pty, Ltd., Australia) for the detection of IgM antibodies against Leptospira species was performed according to the manufacturer's instructions. The results were calculated as "Panbio units" with results of Յ9.0, 9.0 to 11.0, and Ն11.0 defined as negative, equivocal, and positive, respectively. Samples that initially returned an equivocal result were retested. An ICT (Leptotek; Organon-Teknika, The Netherlands) for the detection of Leptospira IgM antibodies was performed according to the manufacturer's instructions. All results were read by eye by the same operator and recorded as positive, equivocal, or negative for the presence of specific IgM antibody. The MAT for Leptospira antibodies was performed by reference laboratories in The Netherlands and Australia. Samples 1 to 36 were assessed at WHO/FAO/OIE Collaborating Centre for Reference and Research on Leptospirosis, KIT Biomedical Research, Amsterdam, The Netherlands (2). Samples 37 to 186 were assessed at the WHO/ FAO/OIE Collaborating Centre for Reference and Research on Leptospirosis in Australia. A patient was considered to have a current or recent Leptospir...

La evidencia serológica de leptospirosis en pacientes con sospecha clínica de dengue en el estado de Ceará, Brasil

“…The ELISA showed higher positivity than the immunochromatographic tests, detecting anti-Leptospira antibodies in five patients. Sehgal, et al, reported that the immunochromatographic test showed a positivity rate similar to that of the immunoenzymatic assay, in contrast to the results obtained in the present study (19).…”

Leptospira Immunoglobulin-Like Proteins as a Serodiagnostic Marker for Acute Leptospirosis

“…Anti-whole-Leptospira antibodies as detected by IgM ELISA or MAT persist for years after acute leptospirosis (17,33,35,51). Low specificity is a major barrier to the use of whole-Leptospira-based assays in areas of high endemicity and transmission (5,13,18,25,55,61,62). In this study, we found that 29% of sera from leptospirosis patients have positive whole-Leptospira-based IgM ELISA reactions 4 to 6 years after infection.…”

Risk Factors of Leptospirosis in Khuzestan, South West of Iran, 2012

“…The reference standard assay is the microscopic agglutination test (MAT), but in limited resource area due to diagnostic capacity of laboratories, other serological test measuring anti leptospira -IgM antibodies are used to detect recent or current leptospirosis (2,(14)(15)(16). Cross reaction IgM-antibody may be associated with other spirochetes organisms and autoimmune diseases (5).…”