Rh factor

noun

a blood group antigen possessed by Rh-positive people; if an Rh-negative person receives a blood transfusion from an Rh-positive person it can result in hemolysis and anemia

• Syn: ↑rhesus factor, ↑Rh

• Hypernyms: ↑antigen

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noun also rh \\äˈrāch-, ȧˈ(r)āch-\

Usage: usually capitalized R

Etymology: rhesus monkey (in which it was first detected)

: a substance or one of a group of substances that is present in the red blood cells of a large majority of persons and in those of other higher animals, is prob. an agglutinogen, is inherited according to Mendelian principles, and is capable of inducing intense antigenic reaction under suitable circumstances (as in repeated transfusion of Rh-positive blood to an Rh-negative person) — called also Rh antigen, rhesus factor; compare hr factor

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/ahr"aych" fak'teuhr/, Physiol.

any of a type of specific antigen present on the surface of red blood cells, persons having inherited such antigens being designated Rh+ (Rh positive) and persons lacking them, a much smaller group, being designated Rh- (Rh negative): blood of Rh- persons is incompatible with Rh+ blood because of antibody reaction, and an Rh- woman who bears an Rh+ baby will have formed antibodies to the fetal blood that, unless removed from her bloodstream by apheresis in a subsequent pregnancy, will be carried across the placenta and destroy red blood cells of the next Rh+ fetus, resulting in erythroblastosis in the newborn.

[1940-45; so called because first found in the blood of rhesus monkeys]

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Rh factor UK [ˌɑːr ˈeɪtʃ ˌfæktə(r)] US [ˌɑr ˈeɪtʃ ˌfæktər] noun [singular] medical

rhesus factor

Thesaurus: heart, blood and circulation_hyponym

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Rh factor,

an antigen found in the red blood cells of most human beings and the higher mammals. Blood containing this substance is Rh positive and does not combine favorably with blood which is Rh negative and lacks this substance. »

The presence or absence of the Rh factor is governed by a dominant gene, which means that when Rh-positive and Rh-negative genes are paired, the resulting children are always Rh-positive (J. Randal).

Also, Rhesus factor.

╂[< rh(esus); it was first discovered in the blood of the rhesus monkey]

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/ˌɑɚˈeıʧ-/ noun [noncount]

medical : a substance that is present in the red blood cells of most people

◇ If you do not have Rh factor in your blood, you can become ill by receiving blood from someone who has Rh factor. — called also Rhesus factor — see also

RH-NEGATIVE

,

RH-POSITIVE