A blood type is a description of an individuals characteristics of red blood cells due to substances (carbohydrates and proteins) on the cell membrane. The two most important classifications to describe blood types in humans are ABO and the Rhesus factor (Rh factor). There are 46 other known antigens, most of which are much rarer than ABO and Rh. Blood transfusions from incompatible groups can cause an immunological transfusion reaction, resulting in hemolytic anemia, renal failure, shock, and death...
