Blood type
A blood type (also known as a blood group) is a classification of blood, based on the presence and absence of antibodies and inherited antigenic substances on the surface of red blood cells (RBCs). These antigens may be proteins, carbohydrates, glycoproteins, or glycolipids, depending on the blood group system. Some of these antigens are also present on the surface of other types of cells of various tissues. Several of these red blood cell surface antigens can stem from one allele (or an alternative version of a gene) and collectively form a blood group system.[1]
This article is about blood type in humans. For other uses, see Blood type (disambiguation).Blood types are inherited and represent contributions from both parents of an individual. As of December 2023, a total of 45[2] human blood group systems are recognized by the International Society of Blood Transfusion (ISBT).[3] The two most important blood group systems are ABO and Rh; they determine someone's blood type (A, B, AB, and O, with + or − denoting RhD status) for suitability in blood transfusion.