Every cell in our body including red blood cells is covered with special markers called antigens, a substance that triggers the immune system response. Millions of antigens are present on the membrane of red blood cells and are ignored by the immune system because they are self-antigens. However, if a person receives a transfusion of blood that contains different antigens from their own blood, there will be a severe and immediate attack by the cells of the immune system. Therefore, it is important to use the patient’s same blood group for the transfusion. The blood group antigens not only...