description
There are many antigens besides A, B, and Rh. However, neither the donor nor the recipient is tested routinely for these other antigens. However, if a patient has had a previous transfusion or been pregnant, they may have developed antibodies to one of these other antigens. And the recipient may have a transfusion reaction. The presence of such an antibody is determined by doing an antibody screening test by mixing the patient's serum with red cells of a known antigenic makeup.