Two established immunodiagnostic techniques, immunofluorescence and indirect haemagglutination, were compared with ELISA (enzyme-linked immunosorbent assay) using intact promastigotes as antigen for the detection of specific antibodies against Leishmania in the serum of patients with visceral or mucosal leishmaniasis from the Sudan. The ELISA was found to be more sensitive and more specific than either of the other two tests.

The commonly used diagnostic methods for visceral leishmaniasis (kala-azar) have many disadvantages. ELISA appears to be a more easily applied test for diagnosis, follow-up of treatment and epidemiology. The preparation of the ELISA antigen has given rise to difficulties in standardization since these are usually soluble. Intact cultured promastigotes have been used to develop an ELISA which is sensitive and specific while avoiding the extra handling which is a source of variability and lack of reproducibility. When tested on sera from kala-azar patients and patients with other tropical diseases, this ELISA was able to detect specific antibodies at very high serum dilutions. It is thus promising as a screening method applicable in the field.

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