Written By: Usman
Blood type is the categorization of Blood which is based on the presence or absence of specific antigens on the surface of Red blood cells. The antigen is the substance that can activate the immune system ( if that antigen is foreign) of a person. Depending on the presence or absence of antigens there are four major types of blood groups and are.
Blood Types
- A Blood group
- B Blood group
- AB blood group
- O Blood group
- A blood group has antigen A on the surface of red blood cells and there is a B antibody in the plasma.
- B blood group has B antigen on the surface of red blood cells and there is an A antibody in the plasma.
- AB blood group has both A & B antigens on the surface of red blood cells but neither A nor B antibodies in the plasma.
- O blood group has neither A antigen nor B antigen but both A& B antibodies in the plasma.
- In addition to antigen, there is a protein called RH factor on which the (-) & (+) blood group is based. If the RH factor is present then the blood group would be (+) and if the RH factor is absent then the blood group would be (-). So in this way, there is a total of eight blood groups.
- A(+) A(-) B(+) B(-) AB(+) AB(-) O(+) O(-)
Blood Transfusions
- Blood Transfusion is a critical step in clinical practice and should be carefully done.
- Blood Transfusion is done on the basis of antigen and RH factor
- A blood group can be transfused to A blood group and AB blood group receipt.
- B Blood group can be transfused to B Blood group and AB blood group receipt.
- AB blood group can be transfused to AB blood group receipt only.
- O blood group can be transfused to all blood groups A,B, AB, and O ( the reason for this is that the O blood group has no antigen on red blood cells)
- In terms of RH factor, RH factor negative can be transfused to both (-) and (+) and RH (+) can only be transfused to RH (+).
Universal Donor Blood group
O(-) is known as the universal Donor Blood group because it can be transfused to any type of blood group receipt.
