Explain how blood types are determined?

Blood types are determined by the presence or absence of specific antigens on the surface of red blood cells. These antigens are inherited from our parents, and they determine which blood types we can receive and donate.

There are four main blood groups: A, B, AB, and O. People with blood group A have only A antigens on their red blood cells, people with blood group B have only B antigens, people with blood group AB have both A and B antigens, and people with blood group O have neither A nor B antigens.

In addition to the ABO blood group system, there is also the Rh factor. The Rh factor is another antigen that can be present on red blood cells. People who have the Rh factor are Rh-positive, while those who don't have the Rh factor are Rh-negative.

The combination of ABO blood group and Rh factor determines a person's complete blood type. For example, someone with A-positive blood has A antigens and the Rh factor, while someone with B-negative blood has B antigens but not the Rh factor.

Blood transfusions are only safe if the donor's blood type is compatible with the recipient's blood type. If a person receives a blood transfusion with an incompatible blood type, the recipient's immune system will attack the donor's red blood cells. This can lead to a serious condition called hemolytic transfusion reaction.

To avoid hemolytic transfusion reactions, blood banks carefully test donor blood to determine the blood type before it is transfused into a recipient.