Human blood types

All blood is made out of the same basic elements, but they are still not completely the same. Blood types are determined by the abcense of the presence of specific antigens (substances that will possible trigger and immune response if they are foreign to a body), Because of this if the wrong type of blood is transfused into a patient, its immune system will attack the blood, so safe transfusion depend on blood types.

The four major blood type groups are determined by the presence or absence of two antigens, A and B, which are on the surface of red blood cells:

• Group A – A antigen on red cells (B antibody in the plasma)

• Group B – B antigen on red cells (A antibody in the plasma)

• Group AB – A and B antigens on red cells (neither A nor B antibody in the plasma)

• Group O – Neither A nor B antigens on red cells (A and B antibody are in the plasma)

Diagram from RedCrossBlood.org

Reference

The American National Red Cross. (2017). Blood Types. [Web portal]. Retrieved from http://www.redcrossblood.org/learn-about-blood/blood-types