Which blood type is considered the 'universal donor'?

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Multiple Choice

Which blood type is considered the 'universal donor'?

Blood type compatibility for transfusions depends on the A and B antigens present on red blood cells and the antibodies in the recipient’s plasma. The universal donor for red blood cell transfusions is the type that has no A or B antigens on its RBC surface, so it won’t be targeted by anti-A or anti-B antibodies in any recipient. That makes type O the best answer. In practice, the most universally compatible donor as a safety-net in emergencies is O negative, because it also lacks the Rh antigen, allowing it to be given to patients of any ABO and Rh type when the patient's blood type isn’t known. By contrast, cells with A, B, or both antigens can provoke an immune reaction in recipients who don’t share those antigens.

Blood type compatibility for transfusions depends on the A and B antigens present on red blood cells and the antibodies in the recipient’s plasma. The universal donor for red blood cell transfusions is the type that has no A or B antigens on its RBC surface, so it won’t be targeted by anti-A or anti-B antibodies in any recipient. That makes type O the best answer. In practice, the most universally compatible donor as a safety-net in emergencies is O negative, because it also lacks the Rh antigen, allowing it to be given to patients of any ABO and Rh type when the patient's blood type isn’t known. By contrast, cells with A, B, or both antigens can provoke an immune reaction in recipients who don’t share those antigens.

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