A new method for the demonstration of leukocyte antibodies by the complement consumption test is described. For this test active serum and the complement of the examined serum itself is used. In the presence of antibodies against the antigen used, complement consumption takes place during the antigen-antibody reaction. This consumption can be estimated while titrating C' by the difference between the first completely hemolyzed test tube in the lower row (serum to which no antigen had been added), and the test tube with complete hemolysis in the upper row (serum with added antigen).
Two hundred-eighty normal sera, 105 sera of patients suffering from variouts internal diseases and 78 sera from patients with disorders of the blood were examined. The complement consumption test gave positive results more often than did the leukoagglutination method.
The method described was also successful in the demonstration of thrombocyte antibodies. We believe that it is equally suited for the detection of various tissue antibodies.