Which statement about blood type O is true?

Which statement about blood type O is true?

• A. It is the universal donor
• B. It is the universal recipient
• C. It cannot donate to anyone
• D. It is the rarest blood type

Answer: (A)

Blood type O is defined by the absence of A and B antigens on red blood cells. Because there are no A or B antigens for recipient antibodies to attack, O red cells can be given to people of any ABO type, so it’s considered the universal donor in RBC transfusions. In practice, the strict universal donor is O negative, since that also lacks Rh antigen and won’t provoke Rh incompatibility. However, people with type O blood have anti-A and anti-B antibodies in their plasma, so they can only receive type O blood. The other statements aren’t true: AB is the universal recipient, type O is not the rarest blood type, and type O can donate to others.

Blood type O is defined by the absence of A and B antigens on red blood cells. Because there are no A or B antigens for recipient antibodies to attack, O red cells can be given to people of any ABO type, so it’s considered the universal donor in RBC transfusions. In practice, the strict universal donor is O negative, since that also lacks Rh antigen and won’t provoke Rh incompatibility. However, people with type O blood have anti-A and anti-B antibodies in their plasma, so they can only receive type O blood. The other statements aren’t true: AB is the universal recipient, type O is not the rarest blood type, and type O can donate to others.