Question

blood is known as the universal donor, which means it can be given to anyone needing a blood transfusion.

blood is known as the universal recipient, which means it can receive all blood types during a transfusion.

Answer 1

Both original sentences are incomplete — they need the specific blood types named. Correct versions:

- "Type O negative blood is known as the universal donor, which means red blood cells from O negative donors can generally be given to people of any blood type in a transfusion."
- "Type AB positive blood is known as the universal recipient, which means people with AB positive blood can generally receive red blood cells from any ABO and Rh type."

Brief explanation and caveats:
- ABO: O red cells lack A and B antigens, so they are less likely to trigger anti-A or anti-B antibodies in the recipient. Rh: negative lacks the Rh(D) antigen, so O negative can be given to both Rh+ and Rh− recipients.
- AB+: AB red cells have both A and B antigens and recipients do not have anti-A or anti-B antibodies, so they can accept red cells from any ABO type; being Rh positive lets them accept Rh+ as well.
- Plasma is the opposite: AB plasma is the "universal plasma donor" (it has no anti-A or anti-B antibodies), while O plasma contains both anti-A and anti-B.
- Real-world practice: blood is ideally crossmatched and antibody-screened before transfusion. O negative is used as an emergency/universal donor for uncrossmatched red cells, but there are exceptions and clinical considerations (e.g., reserving O− for women of childbearing potential, rare antibodies).