Final answer:
A person with AB blood type expresses both A and B antigens on their red blood cells. They are considered universal recipients because they can receive blood from any ABO blood type.
Step-by-step explanation:
A person with the AB blood type has both A and B antigens on the surface of their red blood cells (RBCs). In the ABO blood group system, antigen A is associated with type A blood, antigen B with type B blood, and individuals with AB blood type express both antigens. In contrast, those with type O blood do not have either A or B antigens. The identification of different blood groups has important implications for blood transfusions, as it is crucial to match donor and recipient blood types to prevent adverse reactions. For example, people with type AB blood can receive blood from any ABO type, making them universal recipients.
Beyond the ABO system, there's also the Rh antigen system, which includes the familiar terms 'positive' and 'negative' in blood types, referring to the presence or absence of the Rh factor, another surface antigen. Compatibility in blood transfusions requires attention to both ABO and Rh blood group systems.