ABSTRACT
Anti-K alloantibody is a type of red blood cell (RBC) antibody which is generated through immunization. It is well noted that the anti-K antibody causes hemolytic transfusion reactions. Although Koreans generally do not have the K antigen on RBCs, we report a rare case of transfusion-related anti-K antibody in Korean patient. Just twelve pints of packed RBCs had been transfused to the patient before the anti-K was identified for the first time, but the donor information about Kell phenotype (K or k) was not available. The anti-K had been continuously detected, and the patient neither received immunoglobulins nor experienced bacterial infections which could generate anti-K antibody. Therefore we believe that her anti-K is the truly positive, previously transfused packed RBCs-related alloantibody. The packed RBCs transfused to our patient were likely to be donated from other races. The pre-transfusion irregular antibody detection test should be performed carefully to detect very rare RBC alloantibodies.