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Blood type test
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A blood type test tells you which of the four main groups a person's blood belongs to: A, B, O, or AB. The grouping is based on the agglutination pattern of their red blood cells, that is, the conditions under which the cells stick together and form clumps.
The group is determined by the ABO antigens, markers that sit on the surface of the red blood cell. Every red blood cell carries its own label, and the plasma holds antibodies that recognize it. By about six months of age, a person with normal immune defenses makes anti-A and anti-B antibodies on their own; an antibody is a defense protein that latches onto what it recognizes.
That is why one piece of information is not enough before a transfusion. ABO and Rh types are determined for both the person who will receive the blood and the donated unit, and the recipient's plasma is also screened to see whether it already carries antibodies.
In brief
A blood type test sorts blood into four main groups, A, B, O, or AB, based on how red blood cells clump together.
ABO antigens sit on the red blood cell surface, and an immunocompetent person makes anti-A and anti-B antibodies on their own by about six months of age.
Every red blood cell carries its own label, and the plasma holds antibodies that recognize it.
Before a transfusion, ABO and Rh types are determined for both the recipient and the donated unit, and the plasma is screened for antibodies.
Sources (2)
- National Center for Biotechnology Information, StatPearls PublishingABO Blood Group System, StatPearlsPublished
- National Center for Biotechnology Information, StatPearls PublishingPretransfusion Testing, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated