Blood Typing
Blood typing, in its most simple form, describes the process of identifying the group to which an individual sample of blood belongs. Some thirty blood groups are recognised by the International Society of Blood Transfusion, of which the ABO group is the most common. Blood groups can be classified according to the protein coating that is present on red bloods cells, which are suspended in plasma alongside white cells and platelets.
This protein coat consists of inherited antigenic substances and can be divided into four primary groups according to the presence of oligosaccharide, which is a polymer comprising component sugars that plays a number of roles in blood development and recognition at the cellular level.
The four primary blood groups are A, of which A oligosaccaride is present, B, of which B oligosaccaride is present, AB, of which both A and B oligosaccarides are present, and O, of which neither A nor B oligosaccarides are present although their precursor, H oligosaccaride, is present. Beyond these main blood groups there are a number of further classifications, including A1 Negative and Positive, A1B Negative and Positive, A2 Negative and Positive, A2B Negative and Positive, B Negative and Positive, and O Negative and Positive. Some of these groups are rare, determined by the number of donors required for screening before a compatible donor is found.
Blood typing is essential in order to provide effective medical treatment, where incompatible blood transfusions can in some cases lead to death. It is also important in helping people track down or determine blood relatives as part of a DNA test. Blood typing usually falls under the ABO or Rhesus blood group systems.
