Also called blood type, blood group is the classification of blood that is based upon the absence or presence of certain antibodies or inherited antigenic particles that are present on the blood cells. The red blood cells contain these antigens which might have proteins, glycoproteins, carbohydrates, and glycolipids. Antigens (See: Antigen) are substances that trigger an immune response to foreign substances. Blood groups are inherited from the parents. There are mostly eight common types of blood groups, but 35 blood groups in all. A blood group generally describes 30 compounds present on the surface of a red blood cell. A person’s blood group is the distinct combination of all of these 30 antigens among all the possibilities. The ABO system is the most common and important blood group system. The RhD antigen further determines the blood group’s subdivision. The ABO system has A+ with RhD positive antigen, A – with RhD negative antigen, B + with RhD positive antigen, B – with RhD negative antigen, O + with Rhd positive antigen, O – with RhD negative antigen, AB + with RhD positive antigen, and AB – with RhD negative antigen. While blood group A has B antibody in the plasma, blood group B has A antibody in the plasma. Group AB has both A and B antigens in the red blood cells, but both A and B antibodies are not present in the plasma. Group O does not have A and B antigens in the red blood cells, but has both A and B antibodies in the plasma. Group O can be transfused to anybody (universal donor) and group A can be transfused to groups B and AB. Group AB can be transfused to other AB groups, but they can receive from all others. Also, group AB is a universal plasma donor. It is important to note that transfusion should be done only with receiver’s own blood type or compatible group in order to avoid transfusion risks such as acute hemolytic reaction that leads to the destruction of red blood cells, renal failure, and shock. To avoid this, a process called cross-matching is conducted. In this process, the donor’s red blood cells and the recipient’s blood serum are mixed to see if they form clumps. If they form clumps, both the blood groups are incompatible. People with diabetes can donate blood in case they do not have any complications and if their diabetes is well under control with diet and oral medications. People who take insulin can also donate blood under certain conditions, but should consult their doctors first. However, people with diabetes have to strictly watch their blood glucose levels after the blood donation. People with diabetes can receive blood, but that does not alter their diabetes. Blood transfusion is not a remedy for diabetes.