Human blood grouping
Human blood grouping is based on the presence or absence of certain proteins, called antigens, on the surface of red blood cells. There are many different blood group systems, but the most well-known are the ABO and Rh systems.
ABO system: The ABO system is based on the presence or absence of two antigens, called A and B, on the surface of red blood cells. There are four blood types in the ABO system: A, B, AB, and O.
- Type A blood has only the A antigen on red blood cells
- Type B blood has only the B antigen on red blood cells
- Type AB blood has both the A and B antigens on red blood cells
- Type O blood has neither the A nor B antigen on red blood cells
Rh system: The Rh system is based on the presence or absence of another antigen, called the Rh factor, on the surface of red blood cells. If someone has the Rh factor, they are Rh-positive (Rh+), and if they do not have the Rh factor, they are Rh-negative (Rh-).
Other blood group systems: There are many other blood group systems that are less well-known but still important for medical purposes, such as the Kell, Duffy, and Kidd systems. Each system is based on a different set of antigens and can be used for more specific matching in blood transfusions or organ transplants.
Blood grouping is important for blood transfusions and organ transplants, as a mismatch in blood type can lead to a potentially life-threatening reaction by the recipient’s immune system. Therefore, it is important to determine a person’s blood type before any medical procedures involving blood or blood products.