Hemolytic Transfusion Reaction

Excerpt

A transfusion is defined as an infusion of whole blood or any one of its components. Transfusions, like any other medical intervention, have benefits and risks, and one risk is a hemolytic transfusion reaction (HTR). Hemolysis is the rupture and subsequent leakage of red blood cells (RBCs) into intravascular (in the circulation) or extravascular (in the reticuloendothelial system) spaces. HTRs can also be immune-medicated or non–immune-mediated.

Immune HTRs often occur due to mismatch or incompatibility of the patient with the donor products and are classified as acute versus delayed hemolytic reactions. Acute hemolytic reactions occur within 24 hours of transfusion, and delayed hemolytic reactions are seen after 24 hours. Delayed reactions usually present 2 weeks after transfusion but can occur up to 30 days post-transfusion. The severity of the hemolytic reaction is dependent on the type and quantity of antigens, alloantibodies, and the presence or absence of complement system activation.

Non-immune hemolysis can be due to thermal, osmotic, or mechanical injury to blood products. Human or systemic errors can cause these forms of hemolysis. HTRs occur most often after the transfusion of packed RBCs but can also occur after the transfusion of other blood products such as plasma, platelets, cryoprecipitate, or whole blood.