Blood typing helps clinicians select compatible blood for transfusion. This lesson introduces the immune reactions that can occur when blood is incompatible and explains how the ABO blood group is determined.
An antigen is a substance that can prompt an immune response when the body recognizes it as foreign. In blood typing, the relevant antigens are marker molecules on the membranes of erythrocytes, also called red blood cells. These markers can be recognized by antibodies in plasma.
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What is an erythrocyte antigen?
A marker molecule on an erythrocyte's membrane that can be recognized by the immune system. A and B antigens determine the ABO group.
What do antibodies do in an incompatible transfusion?
They bind to foreign antigens on donated erythrocytes and may link cells together, triggering agglutination and potentially hemolysis.
How do agglutination and hemolysis differ?
Agglutination is the clumping of erythrocytes; hemolysis is the breakdown of erythrocytes and release of their contents, including hemoglobin.
Which antibodies are found in type O plasma?
Type O plasma normally contains both anti-A and anti-B antibodies, while type O erythrocytes display neither A nor B antigens.
Why is ABO matching important?
Matching helps prevent recipient antibodies from binding to donor erythrocyte antigens, which could cause clumping, cell destruction, and serious complications.
Quiz questions
What determines a person's ABO blood type?Answer: Whether A antigens, B antigens, both, or neither are present on erythrocytes.
Which antibodies are normally found in the plasma of a person with type A blood?Answer: Anti-B antibodies.
What is agglutination in a transfusion reaction?Answer: The clumping of erythrocytes when antibodies bind to antigens on their surfaces.
Why can hemolysis during an incompatible transfusion damage the kidneys?Answer: A large amount of released hemoglobin can overwhelm the kidneys.
A person with type B blood receives donor erythrocytes carrying A antigens. Which recipient antibody can bind to those cells?Answer: Anti-A antibodies.
Based on Anatomy and Physiology 2e by J. Gordon Betts, Kelly A. Young, James A. Wise, Eddie Johnson, Brandon Poe, Dean H. Kruse, Oksana Korol, Jody E. Johnson, Mark Womble, Peter DeSaix (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.