Acute hemolytic transfusion reaction caused by a red cell antibody that was missed by pretransfusion testing using tube method

Pretransfusion testing is very important to prevent transfusion of incompatible red cells, which might result in a hemolytic transfusion reaction. This includes the detection of antibodies in recipients' serum and compatibility testing between donor cells and recipient serum. The most commonly used methods include gel and tube techniques. We present a case in which an anti-E alloantibody was detected by gel method but not by tube testing. As a result, red cells that were retrospectively phenotyped as positive for E antigen were inadvertently selected and transfused after crossmatch using the same tube method. After transfusion, the patient developed signs of hemolytic transfusion reaction. This case highlights the potential risk of transfusion of incompatible red cells when alloantibody detection is solely relied on tube testing.