Type AB Blood.

Human blood is grouped into four different types. These four different types are : A, B, AB, and O. As you might guess, AB is a combination of, well, A and B. Each letter refers to a kind of antigen (protein) on the surface of the red blood cells. Red blood cells and other formed elements only make up about 45% of blood, the other 55% is this watery, sticky substance called plasma. For example, a person with …

…categories... however! There is one type of blood they can not receive. Let's not forget about the Rh factor. Depending upon whether they are Rh+ or Rh-, they can only take blood from someone who has the same Rh antigen as themselves, otherwise the whole antibody illness issue kicks in. Only 4% of the world population has type AB blood, and of that 4%, .7% has type AB- blood. It is very rare and you can see why!