Delayed Overt Hemolytic Transfusion Reaction Due to Anti‐U Antibody

Abstract
A patient is described who developed a delayed hemolytic transfusion reaction, 11 days posttransfusion, caused by anti-U. This case illustrates the difficulty that can occur in distinguishing a delayed transfusion reaction from autoimmune hemolytic disease when the antibody involved is directed against a high incidence blood group antigen.