Human blood group systems

Human blood group systems

The International Society of Blood Transfusion (ISBT) currently recognises 30 major blood group systems (including the ABO and Rh systems). [cite web |url=http://blood.co.uk/ibgrl/ISBT%20Pages/ISBT%20Terminology%20Pages/Table%20of%20blood%20group%20systems.htm |title=Table of blood group systems |accessdate=2006-11-14 |year=2006 |month=October |publisher=International Society of Blood Transfusion ] Thus, in addition to the ABO antigens and Rhesus antigens, many other antigens are expressed on the red blood cell surface membrane. For example, an individual can be AB RhD positive, and at the same time M and N positive (MNS system), K positive (Kell system), and Lea or Leb positive (Lewis system). Many of the blood group systems were named after the patients in whom the corresponding antibodies were initially encountered.

The ISBT definition of a major blood group system is where one or more antigens are "controlled at a single gene locus or by two or more very closely linked homologous genes with little or no observable recombination between them". [cite web |url=http://www.bloodnet.nbs.nhs.uk/ibgrl/ISBT%20Pages/ISBT%20Terminology%20Pages/Terminology%20Home%20Page.htm#Popular |title=Terminology Home Page |accessdate=2006-11-14 |author=ISBT Committee on Terminology for Red Cell Surface Antigens ]

Blood Grouping Procedure

Blood is composed of cells suspended in a liquid. The liquid portion is the plasma, from which therapeutic fractions and derivatives are made.

Suspended in the plasma are three types of cells:
* Red cells carry oxygen
* White cells fight infection
* Platelets stop bleeding in injuries

The most common type of grouping is the ABO grouping. Red Blood Cells have a protein coat on their surface which distinguishes them. According to this blood is divided into four groups:

*A (A oligosaccharide is present)
*B (B oligosaccharide is present)
*AB (A and B oligosaccharides are present)
*O (neither A nor B, only their precursor H oligosaccharide is present)

There are subtypes under this grouping (listed as A1, A2, A1B or A2B…) some of which are quite rare. Apart from this there is a protein which plays an important part in the grouping of blood. This is called the Rh factor. If this is present, the particular blood type is called positive. If it is absent, it is called negative. Thus we have the following broad categories:

* A1 Negative (A1 -ve)
* A1 Positive (A1 +ve)
* A1B Negative (A1B -ve)
* A1B Positive (A1B +ve)
* A2 Negative (A2 -ve)
* A2 Positive (A2 +ve)
* A2B Negative (A2B -ve)
* A2B Positive (A2B +ve)
* B Negative (B -ve)
* B Positive (B +ve)
* O Negative (O -ve)
* O Positive (O +ve)

[Information Courtesy: Indian Red Cross Society, Tamil Nadu Branch.]

How is a blood group categorized as rare?

A rare blood type is any blood type that is difficult to find. A blood type is classified as rare when more than 200 donors have to be screened to find one compatible donor with blood of that type. In the "ABO" system, all Blood belongs to one of four major group: A, B, AB, or O. But there are more than two hundred minor blood groups that can complicate Blood transfusions. These are known as rare blood Types. About one person in 1,000 will inherit a rare blood type. Whereas common blood types are expressed in a letter or two, with maybe a plus or a minus, a fewer number of people express their blood type in an extensive series of letters in addition to their 'ABO' type designation. For example, AB +ve, O -ve, and A1 -ve are rare types)

Table

References

External links

* [http://www.bloodnet.nbs.nhs.uk/ibgrl/ISBT%20Pages/ISBT%20Terminology%20Pages/Table%20of%20blood%20group%20antigens%20within%20systems.htm ISBT Table of blood group antigens within systems] Updated October 2006
* [http://www.ncbi.nlm.nih.gov/projects/mhc/xslcgi.fcgi?cmd=bgmut/home BGMUT] Blood Group Antigen Gene Mutation Database
* [http://science.uwe.ac.uk/StaffPages/NA/Blood%20Group.htm Blood group] The Faculty of Applied Sciences, University of the West of England


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Major human blood group systems — ▪ Table Major human blood group systems system date of discovery main antigens ABO 1901 A1, A2, B, H MNSs 1927 M, N, S, s P 1927 P1, P2 Rh 1940 D, C, c, E, e Lutheran 1945 Lua, Lub Kell 1946 K, k Lewis 1946 Lea, Leb Duffy 1950 Fya, Fyb Kidd 1951… …   Universalium

  • blood group — Med. any of various classes into which human blood can be divided according to immunological compatibility, based on the presence or absence of specific antigens on red blood cells. Also called blood type. Cf. ABO system, Rh factor. [1915 20] * * …   Universalium

  • Blood group — An inherited feature on the surface of the red blood cells. A series of related blood types constitute a blood group system such as the Rh or the ABO system. The frequencies of the ABO and Rh blood types vary from population to population. In the …   Medical dictionary

  • Rh blood group system — Rh redirects here. For Siddharta, see Rh (album). For the band, see The RH Factor. The Rh (Rhesus) blood group system (including the Rh factor) is one of the currently 30 human blood group systems. It is clinically the most important blood group… …   Wikipedia

  • Blood type — (or blood group) is determined, in part, by the ABO blood group antigens present on red blood cells. A blood type (also called a blood group) is a classification of blood based on the presence or absence of inherited antigenic substances on the… …   Wikipedia

  • ABO blood group system — ABO redirects here. For other uses, see ABO (disambiguation). H substance redirects here. For use in inflammation, see histamine. ABO blood group antigens present on red blood cells and IgM antibodies present in the serum The ABO blood group… …   Wikipedia

  • Blood transfusion — Intervention Plastic bag containing packed red blood cells in citrate, phosphate, dextrose, and adenine (CPDA) solution …   Wikipedia

  • Blood plasma — is the straw colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid (all body fluid outside of… …   Wikipedia

  • Kell blood group system — ▪ physiology       classification of human blood based on the presence on the surfaces of red blood cells (erythrocyte) of various antigens (antigen) encoded by the KEL gene. The system, discovered in 1946, is characterized by a high degree of… …   Universalium

  • Rhesus blood group system — The term Rhesus (Rh) blood group system refers to the 5 main Rhesus antigens (C, c, D, E and e) as well as the many other less frequent Rhesus antigens. The terms Rhesus factor and Rh factor are equivalent and refer to the Rh D antigen… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”