Question

Person with blood group AB is considered as universal recipient because he has

• A. both A and B antigens on RBC but no antibodies in the plasma
• B. both A and B antibodies in the plasma
• C. no antigen on RBC and no antibody in the plasma
• D. both A and B antigens in the plasma but no antibodies

Answer 1

The correct option is A both A and B antigens on RBC but no antibodies in the plasma

ABO blood groups are determined by the gene I (isoagglutinin). This gene has three alleles - $I^A$, $I^B$ and $I^O$. $I^A$ allele is responsible for the formation of A antigen, while $I^B$ allele is responsible for the formation of B antigen.

People with blood group A have the A antigen on the surface of their RBCs, and antibodies to antigen B in their plasma.
Persons with blood group B have B antigen on the surface of their RBCs and antibodies against A antigen in their plasma. Type O individuals do not have any antigens on their RBCs but have antibodies for both A and B antigens in their plasma.
Type AB individuals have both A and B antigens but no antibodies in their plasma.

Individuals with blood group AB can receive blood of A, B or O group, while those with blood group O can donate blood to anyone.