The concepts of universal donor and universal recipient are more for simplicity sake as ideally only blood group matched unit is transfused. As red blood cells of blood group O-negative carry 'no antigen', it can be given to any other group and is thus called universal donor. Blood group O-positive cells cannot be given to any Rh-negative individual. In contrast, the plasma of AB blood group contains no ABO antibodies and can thus receive red cells of any ABO blood group. Similarly, plasma from type AB group can be transfused to individuals of any blood group while individuals with blood group O can receive plasma from any blood group.