Editing Blood type (section)

===Universal donors and universal recipients===
[[File:US Navy 060105-N-8154G-010 A hospital corpsman with the Blood Donor Team from Portsmouth Naval Hospital takes samples of blood from a donor for testing.jpg|thumb|right|220px|A hospital worker takes samples of blood from a donor for testing]]

In transfusions of red blood cells, individuals with type O Rh D-negative blood are often called universal donors. Those with type AB Rh D-positive blood are called universal recipients. However, these terms are only generally true with respect to possible reactions of the recipient's anti-A and anti-B antibodies to transfused red blood cells, and also possible sensitization to Rh D antigens. One exception is individuals with [[hh antigen system]] (also known as the Bombay phenotype) who can only receive blood safely from other hh donors, because they form antibodies against the H antigen present on all red blood cells.<ref>{{cite book |title=Harrison's Principals of Internal Medicine |last=Fauci |first=Anthony S. |author2=Eugene Braunwald |author3=Kurt J. Isselbacher |author4=Jean D. Wilson |author5=Joseph B. Martin |author6=Dennis L. Kasper |author7=Stephen L. Hauser |author8=Dan L. Longo |year=1998 |publisher=McGraw-Hill |isbn=0-07-020291-5 |page=[https://archive.org/details/harrisonsprincie14harr/page/719 719] |url-access=registration |url=https://archive.org/details/harrisonsprincie14harr }}</ref><ref>{{cite web |url=https://www.webmd.com/a-to-z-guides/blood-type-test |title=Universal acceptor and donor groups |publisher=Webmd.com |date=2008-06-12 |access-date=2010-08-01 |archive-date=2010-07-22 |archive-url=https://web.archive.org/web/20100722071429/http://www.webmd.com/a-to-z-guides/blood-type-test |url-status=live }}</ref>

Blood donors with exceptionally strong anti-A, anti-B or any atypical blood group antibody may be excluded from blood donation of high plasma volume blood products. In general, while the plasma fraction of a blood transfusion may carry donor antibodies not found in the recipient, a significant reaction is unlikely because of dilution.

Additionally, red blood cell surface antigens other than A, B and Rh D might cause adverse reactions and sensitization, if they can bind to the corresponding antibodies to generate an immune response.  Transfusions are further complicated because [[platelet]]s and [[white blood cell]]s (WBCs) have their own systems of surface antigens, and sensitization to platelet or WBC antigens can occur as a result of transfusion.

For transfusions of [[Plasma (blood)|plasma]], this situation is reversed.  Type O plasma, containing both anti-A and anti-B antibodies, can only be given to O recipients.  The antibodies will attack the antigens on any other blood type.  Conversely, AB plasma can be given to patients of any ABO blood group, because it does not contain any anti-A or anti-B antibodies.