How we approach transfusions in a patient with high risk of alloimmunization from McLeod phenotype

McLeod phenotype—caused by the missing Xk protein—is a very rare red cell phenotype, one characteristic of McLeod syndrome, and sometimes associated with X‐linked chronic granulomatous disease (CGD). Diagnosis of McLeod phenotype is important for appropriate transfusion management, because red blood cells from all healthy donors will have the Xk protein with its Kx antigen and can lead to red cell antibody formation without the ability to find compatible McLeod phenotype blood for transfusion. We offer a review and approach to diagnosis of the McLeod phenotype and special transfusion considerations.