Which blood type is the universal donor?

Which blood type is the universal donor?

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

Answer: (A)

Compatibility in ABO transfusions hinges on the presence of A and B antigens on red blood cells. Type O blood lacks both A and B antigens on the surface of its red cells, so there are no A or B targets for a recipient’s anti-A or anti-B antibodies. Because of that absence, type O red cells can be given to individuals of any ABO type without triggering an antibody-mediated reaction. In practice, the true universal donor for red cells is often considered type O negative, since it also lacks the Rh antigen, further minimizing incompatibility. The other blood types carry A and/or B antigens, which can be recognized by a recipient’s antibodies if the transfusion is not matched, so they aren’t universal donors.

Compatibility in ABO transfusions hinges on the presence of A and B antigens on red blood cells. Type O blood lacks both A and B antigens on the surface of its red cells, so there are no A or B targets for a recipient’s anti-A or anti-B antibodies. Because of that absence, type O red cells can be given to individuals of any ABO type without triggering an antibody-mediated reaction. In practice, the true universal donor for red cells is often considered type O negative, since it also lacks the Rh antigen, further minimizing incompatibility. The other blood types carry A and/or B antigens, which can be recognized by a recipient’s antibodies if the transfusion is not matched, so they aren’t universal donors.