A rapid, quantitative enzyme-linked immunosorbent assay (ELISA) for the immunodiagnosis of Chagas' disease

A rapid, quantitative enzyme-linked immunosorbent assay (ELISA) for the immunodiagnosis of Chagas' disease is described. The ELISA was standardized with the Falcon assay screening test (F.A.S.T.) system using a purified Trypanosoma cruzi epimastigote fraction (PEF) obtained by ion exchange chromatography. The ELISA technique and an indirect immunofluorescence (IIF) test were used to search for T.cruzi--specific IgG antibodies in 73 patients with chronic Chagas' disease, 58 patients with heterologous infections and 20 healthy controls. The ELISA exhibited 98.6% sensitivity and 98.7% specificity, whereas the sensitivity and specificity of the IIF test were 94.5% and 96.2%, respectively. The excellent performance with regard to sensitivity and specificity, as well as the short assay time make the F.A.S.T. system--based ELISA with PEF a potentially useful tool in screening for antibodies against T. cruzi.