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Multi‐centre evaluation of repeatability and reproducibility of the direct agglutination test for visceral leishmaniasis
Author(s) -
Boelaert M.,
El Safi S.,
Mousa H.,
Mbati J.,
Gurubacharya V. L.,
Shrestha J.,
Jacquet D.,
De Muynck A.,
Le Ray D.,
Boelaert M.,
Van der Stuyft P.
Publication year - 1999
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1046/j.1365-3156.1999.00348.x
Subject(s) - reproducibility , repeatability , direct agglutination test , visceral leishmaniasis , medicine , kappa , leishmaniasis , serology , veterinary medicine , immunology , mathematics , chemistry , antibody , chromatography , geometry
Summary objective To evaluate the repeatability and reproducibility of the serological direct agglutination test (DAT) for visceral leishmaniasis (VL) with aqueous antigen in a multi‐centre study in VL‐endemic areas in Sudan, Kenya and Nepal. methods Repeatability within each centre and reproducibility between the centres' results and an external reference laboratory (Belgium) was assessed on 1596 triplicate plain blood samples collected on filter paper. results High kappa values (range 0.86–0.97) indicated excellent DAT repeatability within the centres. The means of the titre differences between the reference laboratory and the centres in Sudan, Kenya and Nepal (2.3, 2.4 and 1.1, respectively, all significantly different from 0) showed weak reproducibility across centres. 95% of the titre differences between the reference laboratory and the respective centres were accounted for by large intervals: 0.6–9 fold titre variation for Sudan, 0.7–8 fold for Kenya and 0.26–4 fold for Nepal. conclusion High repeatability of DAT confirms its potential, but reproducibility problems remain an obstacle to its routine use in the field. Reproducibility was hindered by alteration of the antigen through temperature and shaking, especially in Kenya and Sudan, and by nonstandardization of the test reading. DAT handling procedures and antigen quality must be carefully standardized and monitored when introducing this test into routine practice.