An accident victim was successfully transfused with blood from the father whose blood, group is AB. The blood group of the accident victim is

Analyze the question: The victim was transfused successfully with blood from a donor whose group is AB. We need the victim's blood group, so we have to work out which recipients can safely receive AB blood.

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

| Group | Antigens on RBC | Antibodies in plasma | |---|---|---| | A | A | anti-B | | B | B | anti-A | | AB | A and B | none | | O | none | anti-A and anti-B |

A recipient's plasma must not contain antibodies against the donor's red cell antigens. Otherwise the donor cells clump (agglutinate).

Solution:

• Donor AB has both A and B antigens.
• Group A recipient: has anti-B, which attacks the B antigen, so it is not safe.
• Group B recipient: has anti-A, which attacks the A antigen, so it is not safe.
• Group O recipient: has both anti-A and anti-B, so it is not safe.
• Group AB recipient: has no antibodies, so it is safe.

AB blood can only be given safely to an AB recipient. AB individuals are called universal recipients, but AB donors can give only to AB.

Answer: The victim's blood group is AB, which is option C.

Tip: Remember "AB can receive from all, but give only to AB." Match the donor's antigens against the recipient's antibodies. If the recipient has no antibody against those antigens, the transfusion is safe.