How Is Blood Categorized?
Antigens are either sugars or proteins on the outside of red blood cells. They are different between people because of genetic variations. They play a key role in certain body functions, such as identifying harmful cells that may lead to disorders, keeping the structure of red blood cells, and carrying other molecules in between cells. Researchers classify different types of blood based on two forms of antigens: Rh antigens and ABO antigens. This classification is important for many medical applications. [2]