Risks of Giving Uncrossmatched Red Cells

Abstract

Safe transfusion practice dictates that crossmatched red cells should be transfused if the patient is stable enough to wait for the crossmatch testing to be completed. In patients who lack red cell alloantibodies (outside of the ABO blood group system), a fast crossmatch can be performed once the antibody identification is known. Patients with red cell alloantibodies will require a slower, full serologic crossmatch. For those situations where the patient cannot wait for crossmatched blood, ABO compatible but uncrossmatched blood can be transfused. The risk of hemolysis in a patient without red cell alloantibodies is very small; the risk in a patient with red cell alloantibodies is higher, yet transfusion should be undertaken in an actively bleeding patient. Uncrossmatched red cells pose no higher risk of sensitization to “minor” blood group antigens compared with crossmatched red cells.