CHAGAS-DISEASE DIAGNOSIS - EVALUATION OF SEVERAL TESTS IN BLOOD-BANK SCREENING

Blood transfusion is one of the principal routes of transmission of Ch agas' disease, a major endemic disease in Latin America. Methods for b lood screening are not accurate and may yield false results that lead to high social and economic costs. This study compares two methods of diagnosing Chagas' disease (indirect immunofluorescence and hemaggluti nation) and several enzyme-linked immunosorbent assays (ELISAs) with r egard to specificity and sensitivity, by using human sera with known s erologic and parasitologic characteristics, as well as samples with di screpant results on conventional serologic tests. An ELISA using recom binant antigens showed no cross-reactivity with sera that were positiv e for other diseases. All evaluated ELISAs performed well, and their u se may lead to a reduction of more than 50 percent in the number of di scordant sera. Further improvements are needed in view of the complexi ty of the serologic diagnosis of Chagas' disease.