blóðflokkun

Blóðflokkun, also known as blood typing, is a method of classifying blood based on the presence or absence of inherited antigens on the surface of red blood cells. These antigens are typically proteins or carbohydrates. The most common and clinically significant blood group system is the ABO system, which categorizes blood into four main types: A, B, AB, and O. Type A blood has A antigens, type B has B antigens, type AB has both A and B antigens, and type O has neither A nor B antigens.

Another crucial blood group system is the Rh system, which determines if an individual is Rh-positive or Rh-negative. This is based on the presence or absence of the RhD antigen. Most people are Rh-positive, meaning they have the RhD antigen. Blood types are determined by a person's genes, inherited from their parents. For example, a person with type AB blood has inherited one gene for A and one gene for B.

Blóðflokkun is vital in medical transfusions. If incompatible blood types are mixed, the recipient's immune system can recognize the transfused red blood cells as foreign and mount an immune response, leading to a transfusion reaction that can be severe or even fatal. Therefore, before any blood transfusion, the donor's and recipient's blood types are carefully matched. Beyond transfusions, blóðflokkun also plays a role in prenatal care to prevent hemolytic disease of the newborn, and in forensic science for identification purposes.