Blood

Blood transfusion between an incompatible donor and recipient results in agglutination of the red blood cells, causing clogging or blocking of-the capillaries. This is mainly due to the reaction between antigens (A and B) on red blood cells and antibodies (a, b) in the plasma. Individuals with blood group 'O' are without A and B antigens on the red blood cells, and hence they can donate blood to a recipient of any blood group ..