Blood groups are monitored for blood transfer.
∙ A person with blood group 'A' has 'A' antigen on the RBC.
∙ A person with 'B' blood group has 'B' antigen on the surface of the RBC.
∙ A person with 'AB' blood group has both 'A' and 'B' antigens on the surface of the RBC.
∙ A person with blood group 'O' has no antigens on the surface of the RBCs.