DAVID NICHOLLS / SCIENCE PHOTO LIBRARY DAVID NICHOLLS / SCIENCE PHOTO LIBRARY
Blood groups. Computer artwork of red blood cells (erythrocytes) in the shape of the letters A, B, AB and O. This represents the four different blood groups, which are determined by the presence or absence of carbohydrate molecules (antigens) on the surface of red blood cells. There are two types of blood group antigen; A and B. The lack of any antigen gives blood group O. If an incompatible blood type is given during a transfusion it can cause fatal immune reactions.
Model release not required. Property release not required.