Which protein determines whether blood type is positive or negative?
A, B, AB, and O are the four main categories of blood. Each of these blood types is further classified as negative or positive, which is a reference to the blood's Rhesus factor. People who have the antigen in their blood, or Rh factor, are deemed Rh-positive.For example, a person with the A blood type and Rhesus factor in their blood has A-positive blood.It is estimated that more than 85 percent of people throughout the world are Rh-positive. People who do not have the antigen, or are without the Rhesus factor, are Rh-negative.For example, a person with the O blood type and no Rhesus factor in their blood has O-negative blood. Whether or not a person is Rh positive or Rh negative is really only significant with respect to pregnancies., B, AB, and O are the four main categories of blood. Each of these blood types is further classified as negative or positive, which is a reference to the blood's Rhesus factor. People who have the antigen in their blood, or Rh factor, are deemed Rh-positive.