If Suzanne has type A negative blood, she could receive type A negative or type O negative blood. Blood type is first based on whether a person's blood has certain antigens, specified as A or B. The blood types are then called A, which contains the A antigen; B, which contains the B antigen; AB which contains both; or O which contains neither. Blood type is further based on whether it contains the Rh factor, specified positive if it is contained in the blood and negative if it is not. Those that are Rh negative cannot receive blood from Rh positive donors. Further, those with A antigens cannot receive blood containing B antigens. Therefore, Suzanne should receive only A negative or O negative blood.