what is an ABO
The ABO system consists of A, B, AB, and O blood types. People with type A have antibodies in the blood against type B. People with type B have antibodies in the blood against type A. People with AB have no anti-A or anti-B antibodies.People with type O have both anti-A and anti-B antibodies.People with type AB blood are called universal recipients, because they can receive any of the ABO types. People with type O blood are called universal donors, because their blood can be given to people with any of the ABO types.Mismatches with the ABO and Rh blood types are responsible for the most serious, sometimes life-threatening, transfusion reactions. But these types of reactions are rare.eople with type O blood are called universal donors, because their blood can be given to people with any of the ABO types. Mismatches with the ABO and Rh blood types are responsible for the most serious, sometimes life-threatening, transfusion reactions. But these types of reactions are rare.