Risks and adverse outcomes associated with emergency-release red blood cell transfusion.

BACKGROUND Group O red blood cell (RBC) units are used for emergency transfusions and are often uncrossmatched when transfused. We sought to determine the risk of alloimmunization and identify acute adverse outcomes of this practice. STUDY DESIGN AND METHODS The transfusion medicine database was searched for emergency-release transfusion (ERT) episodes from January 2006 through December 2010. The data collected included age and sex of the recipient, blood bank history, survival after the ERT episode, antibody screen results, antibody identifications, and compatibility of released units. RESULTS A total of 1444 ERT episodes took place involving 1407 patients. A total of 4144 RBC units were released. Of the 129 positive antibody screens, 34 had no antibody on further work-up, 14 had autoantibodies, 48 had a single antibody specificity, and 25 had multiple antibody specificities. Seven patients developed an antibody that could be attributed to the ERT episode, and 15 patients developed an antibody after ERT and additional RBC transfusions. There were 32 reported suspected transfusion reactions. No acute hemolytic transfusion reactions were reported. Seven patients were given a total of 10 incompatible RBC units. Of these patients, one developed a delayed serologic transfusion reaction. The rate of alloimmunization attributable to ERT was 3%. Overall, the rate of incompatible transfusion was less than 0.3% and the rate of a delayed hemolytic transfusion reaction was approximately 0.02%. CONCLUSION There is minimal risk associated with the release of emergency uncrossmatched blood in the setting of an acutely bleeding patient. [Correction statement added after online publication 15-Oct-2012: the number of patients with autoantibodies, single antibody specificity and multiple antibody specificity has been update.].