An individual with blood group AB can receive blood from those in blood group(s)

Analyze the question: It asks which blood groups a person with blood group AB can safely receive blood from, which means we need to work out which donors are compatible.

Concept: Blood groups are defined by the antigens on the red blood cells and the antibodies in the plasma.

| Blood group | Antigens on red cells | Antibodies in plasma | |---|---|---| | A | A | anti-B | | B | B | anti-A | | AB | A and B | none | | O | none | anti-A and anti-B |

A transfusion is safe when the recipient's plasma has no antibodies against the antigens on the donor's red cells.

Solution:

• Group AB has no anti-A or anti-B antibodies in its plasma.
• So AB blood does not react against any donor red cells, whether A, B, AB or O.
• Donor A (A antigen): safe
• Donor B (B antigen): safe
• Donor AB (A and B antigens): safe
• Donor O (no antigens): safe

This is why group AB is called the universal recipient. Group O is the universal donor.

Checking the options:

• A. A, B, AB, O: correct, since AB can receive from all groups.
• B. A, AB and O only: leaves out B, which is wrong.
• C. AB only: too restrictive.
• D. A and B only: leaves out AB and O, which is wrong.

Exam tip: Remember "AB = All Blood": AB receives from everyone. "O = Opens to all": O gives to everyone. Also remember that in practice, matching blood groups is still preferred, but in exam questions on universal recipients, the answer is all groups.