An antigen found on the surface of red blood cells. Red blood cells with the antigen are said to be Rh positive (Rh+). Those without the surface antigen are said to be Rh negative (Rh-). Blood used in transfusions much match donors for Rh status as well as for ABO blood group, as Rh- patients will develop anemia if given R+ blood. Rh typing is also [..]

1942, from the first letters of rhesus; so called because the blood group, and its effects, were discovered in the blood of rhesus monkeys (1941).

The presence of certain proteins on the surface of red blood cells. It occurs in most people. People with Rh factor are said to be “Rh positive,” and people without it are said to be “Rh negative.” If a fetus has Rh factor and the woman does not, her immune system will develop antibodies that will destroy fetal blood, which can harm the fetus in an [..]

Any of at least eight antigens which have been genetically determined and may be affixed to the outer layer of an individual's red blood cells. See also: Rh reaction.

a protein found on most people's red blood cells. If you do not have the protein, you are Rh negative. Most pregnant women who are Rh negative need treatment to protect the fetus from getting a b [..]

One of the antigens present on red blood cells. Used in categorizing the type of blood a person has.

An antigen present on the red blood cells of about 85% of people. Called Rh because it was first identified in the blood of rhesus monkeys. Persons with the factor are designated Rh-positive, those lacking the factor are designated Rh-negative.