What is a unique feature of type O blood?

Type O blood is recognized as the universal donor because it lacks A and B antigens on the surface of its red blood cells. This characteristic allows type O blood to be transfused to individuals with any other blood type without the risk of an immune reaction. When a person receives a transfusion, their immune system may react against foreign antigens it does not recognize; since type O blood has no A or B antigens, it is safe for all recipients.

Other blood types, such as A, B, or AB, contain specific antigens that can provoke an immune response in individuals who do not have those antigens. This unique attribute of type O blood makes it an invaluable resource in emergency situations where blood type compatibility is crucial for patient safety. Therefore, in terms of transfusion medicine, type O blood is critical due to its versatility as a donor type.