Abstract
Plasma converted to serum by the addition of bovine thrombin prior to compatibility testing agglutinated all donor red cells. This finding prompted an investigation of bovine thrombin–associated incompatibility that showed that (1) thrombin derived from bovine plasma contains IgG antibodies directed against all human red cells, and (2) excess (> 50 units/mL) bovine thrombin used for conversion of plasma to serum may cause hemagglutination and erroneous serologic test results because of the presence of heteroagglutinins. Immunohematology 1993;9;19.