Intravascular hemolytic transfusion reaction due to anti-Vw+Mia with fatal outcome.

Because of the increasing use of type, screen and hold protocols and minimal surgical blood order protocols in transfusion services, a number of patients are receiving un-cross-matched blood in elective situations. There are many low-frequency red blood cell antigens which are lacking on reagent cells used for antibody screening procedures, and alloantibodies directed against these antigens are relatively common and occur in either natural or immune forms. A case of an intravascular hemolytic transfusion reaction resulting in death is reported. The patients had a naturally occurring anti-Vw+Mia and received 1 U of Vw+Mia-positive donor red cells. It is the 1st documented case of a hemolytic transfusion reaction due to this incompatibility. The potential threat of transfusion reactions due to low-frequency antigens must be recognized by the physicians who design type, screen and hold protocols and it has particular reference to the selection of possible recipients for whom the protocols are applied.