The relative sensitivity and relative specificity of the direct agglutination (DA) test for the diagnosis of human Trypanosoma cruzi infection were studied in human serum samples, with and without previous treatment with 2-mercaptoethanol (2-ME), which were obtained from different areas of Brazil. Results obtained with these tests were related to those obtained with the indirect immunofluorescence (IIF) and indirect haemagglutination (IHA) tests. The DA test results from the sample not previously treated with 2-ME did not agree with those from the IIF and IHA tests. On the other hand, the DA test results from the sample previously treated with 2-ME agreed significantly (99·22%) with those from the IIF and IHA tests. © 1981.755695698Allain, Kagan, An evaluation of the direct agglutination test for Chagas' disease (1974) Journal of Parasitology, 60, pp. 179-184Anthony, Johnson, Souza, Use of micro-ELISA for quantitating antibody to Trypanosoma cruzi and Trypanosoma rangeli (1979) American Journal of Tropical Medicine and Hygiene, 28, pp. 969-973Bombaci, Vattuone, Santamaria, Gardy, Reaccion de aglutinacion directa para Chagas. Analisis de su sensibilidad y specificidad cuando se la emplea en un area no endemica (1976) Revista de la Asociacion Bioquimica Argentina, 41, pp. 28-35Camargo, Revista do Instituto de Medicina Tropical de São Paulo (1964) Growth and differentiation in Trypanosoma cruzi I Origin of metacyclic trypanosomes in liquid media, 6, pp. 93-100Camargo, Fluorescent antibody test for the serodiagnosis of American trypanosomiasis. Tecnical modification employing preserved culture forms of Trypanosoma cruzi in a slide test (1966) Revista do Instituto de Medicina Tropical de São Paulo, 8, pp. 227-234Camargo, Hoshino-Shimizu, Macedo, Pires, Castro, Diagnostico serologico da infecção humana pelo Trypanosoma cruzi. Estudo comparativo de testes de fixação do complemento, imunofluorescencia, hemaglutinação e floculação, em 3624 soros (1977) Revista do Instituto de Medicina Tropical de São Paulo, 19, pp. 254-260Cerisola, Immunodiagnosis of Chagasdisease, hemagglutination and immunofluorescence tests (1970) Journal of Parasitology, 56, pp. 409-410Cerisola, Fatala Chaben, Lazzari, Test de hemaglutinacion para el diagnóstico de la enfermedad de Chagas (1962) Prensa Medica Argentina, 49, pp. 1761-1767Desmonts, Baufine-Ducrocq, Couzineau, Peloux, Anticorps toxoplasmiques naturales (1974) Nouvelle Presse Medicale, 4, pp. 1547-1549Guerreiro, Machado, Da reação de Bordet e Gengou na moléstia de Carlos Chagas como elemento diagnóstico (1913) Brasil Médico, 27, pp. 225-226Kagan, Advances in the immuno-diagnosis of parasitic infection (1974) Zeitschrift für Parasitenkunde, 45, pp. 163-195Kagan, Goldsmith, Zarate-Castaneda, Allain, Evaluation on serologic tests for studies on Chagas' disease (1978) Bulletin of the Pan American Health Organization, 12, pp. 341-348Pagniez, De Grech, Miakovich, Camps, Reaccion de aglutinacion directa para Chagas. Estudio comparativo com a reaccion de Machado Guerreiro sobre 10.000 amostras (1976) Revista de la Association Bioquimica Argentina, 41, pp. 38-42Schmuñis, Szarfman, Coarasa, Guilleron, Peralta, Anti-Trypanosoma cruzi agglutinins in acute human Chagas' disease (1980) American Journal of Tropical Medicine and Hygiene, 29, pp. 170-178Storni, Bolsi, Yanovsky, Reaccion de aglutinacion directa para diagnostico de la enfermedad de Chagas. Utilizacion sistematica del 2-Mercaptoetanol para la eliminacion de las aglutininas inespecificas (1975) Medicina (B. Aires), 35, pp. 67-72Vattuone, Pesce, Evaluacion de un antigeno de aglutinacion de epimastigotas de Trypanosoma cruzi (1971) Boletin Chileno de Parasitologia, 26, pp. 7-10Vattuone, Yanovsky, Trypanosoma cruzi: Agglutination activity of enzyme treated epimastigotes (1971) Experimental Parasitology, 30, pp. 349-355