Blood antibodies and uncrossmatched type O blood.

The immediate transfusion of uncrossmatched type O blood in the initial resuscitation of the trauma victim remains controversial. To examine difficulties in crossmatching blood for later transfusions after use of uncrossmatched type O blood, we undertook a prospective 23-month study at a level I trauma center. One hundred thirty-five severely injured patients received uncrossmatched type O blood during the study period. Sixty-one patients (45%) died and 76 patients (56%) underwent emergent operation. There were no major transfusion reactions. Six patients had blood antigen-antibodies present on admission, and such antibodies developed in three patients during hospitalization. We conclude that uncrossmatched type O blood may be used safely in the exsanguinating patient, but blood antigen-antibodies, which may complicate later crossmatching, can develop after its use.