A hemolytic modification of the hemagglutination test for antibodies against tubercle bacillus antigens.

A specific hemagglutination reaction has been described (1) between the sera of tuberculous experimental animals or human beings and sheep erythrocytes treated with extracts or products of the culture filtrates of tubercle bacilli. Observations on this reaction have been confirmed and extended by other investigators (2-6). The present paper is concerned with a modification of this test which involves the addition of complement to the reaction system and thereby often transforms the reaction from one of hemagglutination to one of hemolysis. This hemolytic phenomenon was first observed while investigating the possibility of using tuberculous patients' own red cells instead of sheep red cells for performing the hemagglutination reaction. It has been independently observed by Fisher and Keogh in studies on the application of the hemagglutination test for tuberculosis in cattle (7); and what appears to be the same phenomenon has recently been observed in serologic studies on trypanosomiasis (8).