Question: what is the difference between blood type a positive and a negative?
Answer: Like A, B and O, the positive or negative component of a person's blood type refers to a molecule which is either present or absent on the surface of their red blood cells. In this case, it's an antigen in a blood group system called the Rh (originally called Rhesus) system. ... If you don't have it, you're Rh negative.