Which blood type is the universal recipient?

• A. Type O
• B. Type A
• C. Type AB
• D. Type B

Answer: (C)

Blood transfusion compatibility hinges on antibodies in the plasma and the antigens on the donor red cells. People have antibodies against the ABO antigens they do not possess. Type AB blood has both A and B antigens on its red cells and, importantly, no anti-A or anti-B antibodies in the plasma. That means AB individuals won’t attack donor cells from any ABO type, so they can receive from A, B, AB, or O. Because of this lack of anti-A and anti-B antibodies, Type AB is the universal recipient in the ABO system. Note that if you consider the Rh factor, the most permissive recipient is AB positive, since the Rh antigen adds another compatibility requirement; AB negative would not accept Rh-positive blood. In the common ABO context, however, AB is the universal recipient.