IgA deficiency is the most common primary immunodeficiency. If a blood transfusion contains IgA protein, the IgA-deficient recipient may develop a severe transfusion reaction, including anaphylaxis. A strong causal connection between IgA deficiency and allergic transfusion reactions has not been established; not all patients with IgA deficiency and anti-IgA antibodies will experience an allergic reaction with a transfusion. At least one acute care pediatric guideline recommends that critically ill children with a history of a severe transfusion reaction or severe IgA deficiency with anti-IgA antibodies receive only red blood cells (RBCs) that are either washed or obtained from IgA-deficient donors, and that only plasma products from IgA-deficient donors be administered when possible. In suspected cases of transfusion-related anaphylaxis, laboratory evaluation and ordering of specialized blood products should be done at the direction of the blood bank medical director.