Person with blood group AB is considered as universal recipient because he has no antigen on RBC and no antibody in the plasma.
| Blood Group | Antigens on RBCs | Antibodies in Plasma | Donor's Group |
| A | A | anti-B | A, O |
| B | B | anti-A | B, O |
| AB | A, B | nil | AB, A, B, O |
| O | nil | anti-A, B | O |