Clinical Presentation - Red Cell Alloimmunization

Occasionally RBC alloimmunization may present as an immediate or delayed hemolytic transfusion reaction. However, usually RBC alloimmunization is clinically silent and discovered only during subsequent pretransfusion testing or routine testing during pregnancy.

If antibody testing is performed in the days or weeks following RBC transfusions, newly formed RBC antibodies may be detected, or if an anamnestic response has occurred, a positive DAT (with or without the presence of antibody in the serum/plasma) may be detected. In the latter case, the alloantibody can be eluted from the patient’s red cells.

In a pregnant woman, if prenatal RBC antibody testing is not performed as recommended, it is possible that the first manifestation could be hemolytic disease of the fetus or newborn.