Editing Blood type (section)

===Red blood cell compatibility===
{{Further|Blood compatibility testing}}
* '''Blood group AB''' individuals have both A and B antigens on the surface of their RBCs, and their [[blood plasma]] does not contain any antibodies against either A or B antigen. Therefore, an individual with type AB blood can receive blood from any group (with AB being preferable), but cannot donate blood to any group other than AB.  They are known as universal recipients.
* '''Blood group A'''  individuals have the A antigen on the surface of their RBCs, and blood serum containing [[IgM]] antibodies against the B antigen. Therefore, a group A individual can receive blood only from individuals of groups A or O (with A being preferable), and can donate blood to individuals with type A or AB.
* '''Blood group B'''  individuals have the B antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the A antigen. Therefore, a group B individual can receive blood only from individuals of groups B or O (with B being preferable), and can donate blood to individuals with type B or AB.
* '''Blood group O''' individuals have no A or B antigens on the surface of their RBCs, and their blood serum contains IgM anti-A and anti-B antibodies. Therefore, a group O individual can receive blood only from a group O individual, but can donate blood to individuals of any ABO blood group (i.e., A, B, O or AB). If a patient needs an urgent blood transfusion, and if the time taken to process the recipient's blood would cause a detrimental delay, O negative blood can be used. Because it is compatible with anyone, there are some concerns that O negative blood is often overused and consequently is always in short supply.<ref name="AABBfive">{{Citation |author1 = American Association of Blood Banks |author1-link = American Association of Blood Banks |date = 24 April 2014 |title = Five Things Physicians and Patients Should Question |publisher = American Association of Blood Banks |work = [[Choosing Wisely]]: an initiative of the [[ABIM Foundation]] |url = https://www.choosingwisely.org/doctor-patient-lists/american-association-of-blood-banks/ |access-date = 25 July 2014 |archive-url = https://web.archive.org/web/20140924075027/https://www.choosingwisely.org/doctor-patient-lists/american-association-of-blood-banks/ |archive-date = 24 September 2014 |url-status = dead }}, which cites
* {{cite web|author1=The Chief Medical Officer's National Blood Transfusion Committee|title=The appropriate use of group O RhD negative red cells|url=https://hospital.blood.co.uk/library/pdf/nbtc_bbt_o_neg_red_cells_recs_09_04.pdf|archive-url=https://web.archive.org/web/20140809134013/https://hospital.blood.co.uk/library/pdf/nbtc_bbt_o_neg_red_cells_recs_09_04.pdf|archive-date=9 August 2014|publisher=[[National Health Service]]|access-date=25 July 2014|year=c. 2008}}</ref> According to the Association for the Advancement of Blood and Biotherapies ([[AABB]]) and the British Chief Medical Officer's National Blood Transfusion Committee, the use of group O RhD negative red cells should be restricted to persons with O negative blood, women who might be pregnant, and emergency cases in which blood-group testing is genuinely impracticable.<ref name="AABBfive"/>

[[Image:Blood Compatibility.svg|right|230px|thumb|'''Red blood cell compatibility chart'''<br />In addition to donating to the same blood group; type O blood donors can give to A, B and AB; blood donors of types A and B can give to AB.]]
{| class="wikitable" style="text-align:center;"
|+ Red blood cell compatibility table<!--
 --><ref name=rbccomp>{{cite web |url=https://chapters.redcross.org/br/northernohio/INFO/bloodtype.html |title=RBC compatibility table |access-date=2008-07-15 |date=December 2006 |publisher=American National Red Cross |url-status=dead |archive-url=https://web.archive.org/web/20080913165654/https://chapters.redcross.org/br/northernohio/info/bloodtype.html |archive-date=2008-09-13 }}</ref><ref name=bloodbook>[https://www.bloodbook.com/compat.html Blood types and compatibility] {{Webarchive|url=https://web.archive.org/web/20100419103919/https://www.bloodbook.com/compat.html |date=2010-04-19 }} bloodbook.com</ref><!--
 -->
|-
! rowspan="2" | Recipient<sup>[1]</sup>
! colspan="8" | Donor<sup>[1]</sup>
|-
! O−
! O+
! A−
! A+
! B−
! B+
! AB−
! AB+
|-
! O−
| style="width:3em" | {{Y}}
| style="width:3em" | {{N}}
| style="width:3em" | {{N}}
| style="width:3em" | {{N}}
| style="width:3em" | {{N}}
| style="width:3em" | {{N}}
| style="width:3em" | {{N}}
| style="width:3em" | {{N}}
|-
! O+
| {{Y}}
| {{Y}}
| {{N}}
| {{N}}
| {{N}}
| {{N}}
| {{N}}
| {{N}}
|-
! A−
| {{Y}}
| {{N}}
| {{Y}}
| {{N}}
| {{N}}
| {{N}}
| {{N}}
| {{N}}
|-
! A+
| {{Y}}
| {{Y}}
| {{Y}}
| {{Y}}
| {{N}}
| {{N}}
| {{N}}
| {{N}}
|-
! B−
| {{Y}}
| {{N}}
| {{N}}
| {{N}}
| {{Y}}
| {{N}}
| {{N}}
| {{N}}
|-
! B+
| {{Y}}
| {{Y}}
| {{N}}
| {{N}}
| {{Y}}
| {{Y}}
| {{N}}
| {{N}}
|-
! AB−
| {{Y}}
| {{N}}
| {{Y}}
| {{N}}
| {{Y}}
| {{N}}
| {{Y}}
| {{N}}
|-
! AB+
| {{Y}}
| {{Y}}
| {{Y}}
| {{Y}}
| {{Y}}
| {{Y}}
| {{Y}}
| {{Y}}
|}
<small>
Table note<br />
1. Assumes absence of atypical antibodies that would cause an incompatibility between donor and recipient blood, as is usual for blood selected by cross matching.
</small>

An Rh D-negative patient who does not have any anti-D antibodies (never been previously sensitized to D-positive RBCs) can receive a transfusion of D-positive blood, but this may cause sensitization to the D antigen, and a female patient could become at risk for [[hemolytic disease of the newborn]].  If a D-negative patient has developed anti-D antibodies, a subsequent exposure to D-positive blood could lead to a potentially dangerous transfusion reaction. Rh D-positive blood should never be given to D-negative women of child-bearing age or to patients with D antibodies, so blood banks must conserve Rh-negative blood for these patients. In extreme circumstances, such as for a major bleed when stocks of D-negative blood units are very low at the blood bank, D-positive blood might be given to D-negative females above child-bearing age or to Rh-negative males, providing that they did not have anti-D antibodies, to conserve D-negative inventory in the blood bank. The converse is not true; Rh D-positive patients do not react to D negative blood.

This same matching is done for other antigens of the Rh system as C, c, E and e and for other blood group systems with a known risk for alloimmunization such as the Kell system, particularly for chronically transfused patients.