“There are a number of different blood types that a person can have, but what’s the difference between them all?” – Yt
“Human blood is grouped into four types: A, B, AB, and O. Each letter refers to a kind of antigen, or protein, on the surface of red blood cells. For example, the surface of red blood cells in Type A blood has antigens known as A-antigens.
“The Rh Factor
“Each blood type is also grouped by its Rhesus factor, or Rh factor. Blood is either Rh positive (Rh+) or Rh negative (Rh-). About 85% of Americans have Rh+ blood.
“Rhesus refers to another type of antigen, or protein, on the surface of red blood cells. The name Rhesus comes from Rhesus monkeys, in which the protein was discovered.”
Read more: Blood Types
