To evaluate the degree of blood product and technical resources wasted as a result of allergic transfusion reactions.Allergic reactions are common, and most are non-severe with rash, urticaria, or pruritus. Management includes treatment of symptoms and completion of transfusion. A quality review demonstrated that 30% of transfusion reaction work-ups at our institution were allergic. This raised the concern of product wastage and unnecessary utilisation of laboratory resources.We conducted a retrospective study of allergic reactions, including type of product implicated, volume of products transfused and discarded, the severity of reaction, the use of medications, the incidence of symptom resolution and the rate of repeat transfusion after the allergic event.Of 179 allergic reactions, non-severe reactions were reported in 75%. Non-severe reactions were associated with red blood cell, whereas most severe reactions were associated with platelets. Few cases had premedication; however, 83% of reactions were treated once symptoms developed, and 96% resolved. Of transfusions, 61% were stopped because of symptoms before the transfusion was completed. Of patients with non-severe reactions and transfusions that were not completed, 36% were transfused again within 48 h, representing 16% of all allergic reactions.Allergic reactions resulted in partial transfusion of the prescribed product in just over half of the cases reviewed. Most of these reactions were non-severe, resolved with treatment and could have been completed, thus representing wastage of both blood products and the expense of the reaction evaluation. Educational efforts to eliminate/minimise this waste are in development.