One of the ABO blood groups is sometimes called the universal donor. Which group do you think it is and why?
Individuals with blood group O are called universal donors. These individuals do not have either A or B antigens on the surface of their RBCs, hut their blood serum contains antibodies against both A and B antigens.
Therefore, group individuals can only receive blood from a group O individual, but they can donate blood to individuals of any ABO blood group (i.e., A, B, O or AB).