blood type


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blood groups

blood groups, differentiation of blood by type, classified according to immunological (antigenic) properties, which are determined by specific substances on the surface of red blood cells. Blood groups are genetically determined and each is characterized by the presence of a specific complex carbohydrate. About 200 different blood group substances have been identified and placed within 19 known blood group systems. The most commonly encountered blood group system is the ABO, or Landsteiner, system. Individuals may contain the A, B, or both A and B antigenic substances, or else lack these substances (type O). In the ABO system an individual who lacks one or more of these antigens will spontaneously develop the corresponding antibodies (agglutinins) shortly after birth. Thus a person with A type blood will naturally produce anti-B agglutinins, a person with B blood will produce anti-A agglutinins, and a person with O blood will produce anti-A and anti-B agglutinins; but a person with AB blood will not produce any agglutinins in this blood group system. Since these agglutinins are always present in the blood, in blood transfusion the donor blood must be compatible with the recipient's blood, i.e., the donor's blood must not contain antigen corresponding to the recipient's antibody. Other blood group systems, such as the MNSs, Lewis, Lutheran, and P systems, are not as important in transfusion because they act like true antigen-antibody systems, i.e., antibodies do not appear in blood plasma until the individual has been immunized by exposure to the other blood group antigens as in previous transfusions. In general, blood group substances are weak antigens, and antibody formation after transfusion occurs less than 3% of the time. Immunization can occur by pregnancy as well as by transfusion. Thus, in the Rh factor blood group system, an Rh-negative mother carrying an Rh-positive fetus produces anti-Rh antibodies against fetal red blood cells that cross the placenta. Since blood type is a genetic trait that is easy to test and the blood type of an individual is related to his or her parent's blood types by the laws of Mendelism (see under Mendel, Gregor), blood group typing is used legally to establish paternity. Anthropologists use the frequency of occurrence of various blood groups as tools to study racial or tribal origins.
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blood type

[′bləd ‚tīp]
(immunology)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
In our study, an interesting finding was that blood type A was found to be at the highest rate in patients with RA and AS with erosive arthritis, which are the most common rheumatic diseases, and blood type O was found to be at the highest rate in patients with SLE, SSc, and SjS, which are among the connective tissue disorders frequently observed with antinuclear antibodies.
The distribution of ABO blood types among the control group was A (32%), B (23%), O (32%), and AB (13%) respectively.
Moreover, our present study provided that in PC patients, non-O blood type was strongly and positively associated with high risk, which was independent of other confounders including the established PC risk factors such as PSA and Gleason score.
Bank system has been tested to the blood bank donors who have been storing their data in the database: "name, blood type, mobile phone number, email "optional".
Antigen antibody agglutination test was performed by slide method for the determination of ABO blood types and Rh factor.
The science behind blood types was actually discovered by Karl Landsteiner in 1900.
People with AB blood had a higher average level of factor VIII than people with other blood types.
The center keeps a database of donors with rare blood types so that they can be contacted when needed and asked to donate.
While receiving blood of the same blood type is best, in an emergency Type O blood can be transfused to people of any blood type.
In her engaging study, Boaz presents her findings through a focus on serology, namely the study of blood types (A, B, O, etc.).
Researchers led by Segurel looked at a particular stretch of DNA in the blood type gene in humans, bonobos, chimpanzees, gorillas, orangutans, gibbons and several species of monkey.