Evaluation of the direct agglutination test based on freeze-dried Leishmania donovani promastigotes for the serodiagnosis of visceral leishmaniasis in Sudanese patients
The direct agglutination test (DAT) based on freeze-dried (FD) Leishmania donovani antigen was evaluated for the serodiagnosis of kala-azar in a rural setting in eastern Sudan. The performance of the FD-DAT was compared with standard liquid antigen (LQ) by testing serum samples and blood samples collected on filter paper of microscopically and PCR-confirmed VL patients, apparently healthy endemic controls and patients with other relevant infectious diseases for the region. In the present study, the FD-DAT had a sensitivity of 96.8% and a specificity of 96.2%. The LQ-DAT had a sensitivity of 91.0% and a specificity of 96.6%. A high degree of agreement (97.3%; r-value 0.94) was observed between the FD-DAT and the LQ-DAT, as well as between the FD-DAT performed on serum samples and corresponding blood samples collected on filter paper (agreement 97.8%; r-value 0.79). The FD-DAT is very suitable as diagnostic test for kala-azar in remote rural conditions as it is sensitive, specific and stable. The antigen is affordable, reproducible and available, which contributes to the sustainability of the DAT as a diagnostic test for VL.
Document Type: Research Article
Affiliations: 1: Blue Nile Research and Training Institute, University of Gezira, Gezira, Sudan 2: Koninklijk Instituut voor de Tropen, Amsterdam, The Netherlands 3: Institute of Nuclear Medicine and Oncology, University of Gezira, Gezira, Sudan 4: Faculty of Medicine, University of Gezira, Gezira, Sudan
Publication date: 2004-10-01