Allergic transfusion reactions: An evaluation of 273 consecutive reactions

Context. - Allergic reaction to transfusion is common. However, the review of a large series of allergic transfusion reactions has not been performed. Objective. - To review a large series of allergic transfusion reactions. Design. - A retrospective review of all reported and evaluated transfusion reactions during a 9-year period at 1 institution was performed. Associated clinical signs and symptoms were evaluated. Setting. - Large, tertiary-care teaching hospital. Results. - A total of 1613 adverse reactions to transfusion were evaluated. Allergic transfusion reactions accounted for 17% (273 of 1613) of the transfusion reactions. Severe allergic reactions (anaphylaxis, anaphylactoid signs and symptoms, and/or hypotension) were observed in 21 patients (7.7% of allergic reactions, or 1.3% of all transfusion reactions). Serum tryptase, a marker for anaphylaxis, was measured in 1 patient and determined to be borderline elevated. Five patients experienced allergic transfusion reactions to autologous red cell transfusions. One patient experienced hives during the transfusion of a major ABO mismatched red blood cell. A wide variety of skin manifestations were observed, but 26 (9.5%) patients did not have skin manifestations. Allergic transfusion reactions were estimated to occur in approximately 1 in 4124 blood components transfused, or 11 in 2338 transfusion episodes. Severe allergic reactions occurred in approximately 1 in 30281 transfusions. No deaths directly attributable to transfusion were observed in this patient group. Conclusions. - The clinical presentation of allergic transfusion reactions was quite variable, and the pathophysiology remains unclear. Recommendations for clinical evaluation and therapy remain problematic and often empirical.