ABSTRACT
The practice of transfusion medicine has evolved over the years as people develop a deeper understanding of the effects of anemia, how particular patients tolerate anemia, coagulation, and the risks associated with transfusion. At first, the utility of transfusion was limited by both the understanding of the ABO system and red blood cell antigens, leading to both acute and delayed hemolytic transfusion reactions. Transfusion of blood products is also still associated with a number of adverse reactions including acute and delayed hemolysis, transfusion-related acute lung injury, transfusion-associated circulatory overload, and transfusion-related immunomodulation. Clinicians should therefore remain mindful that transfusion is not without risk and should only occur in the appropriate setting. Leukocyte reduction has become a nearly universal practice in large blood centers and reduces the risk of febrile nonhemolytic transfusion reactions and human leukocyte antigen-alloimmunization.
