The transfusion dilemma--weighing the known and newly proposed risks of blood transfusions against the uncertain benefits.

Due to its significant role in saving lives, blood transfusion became one of the most commonly used therapies in medicine. In the USA red blood cell transfusions, for instance, are given to an estimated 3-4 million patients per year. However, the accepted benefits of transfusion do not come without harm. Acute transfusion reactions have been estimated to occur in almost one-fifth of total transfusions, with serious reactions in approximately 0.5%. Although methods of blood collection, preparation and storage have improved significantly, potential complications and controversial efficacy, especially of red blood cell transfusions, are still a major concern. One long-standing primary concern has been bacterial and viral contamination but recently other risks have been identified, mostly related to recipient immunomodulation and storage lesion-related changes.