• How do antigens identify blood types and Rh factors?

You have seen how antigens on the surface of a blood cell will identify your blood type. To determine blood types, blood must react with serums containing antibodies.

A reaction resulting in a clump of blood indicates a positive test for a particular antigen. Blood cells can contain A, B, and Rh antigens, while blood plasma can contain A, B, and Rh antibodies. Mixing blood types can result in an immune response that will kill blood cells. This is why blood donors and pregnant women are screened for blood type. It is a good idea to also know your own blood type for the benefit of medical professionals who may need to give you a blood transfusion in an emergency.

Lesson Glossary

antigen: a molecule on the surface of the cell that can be recognized by an antibody

agglutination: the clumping of blood caused by the joining of antigens and antibodies

Rh factor: a group of antigens found in most red blood cells; people with the Rh antigen on their blood cells are considered to be Rh+

Assessment

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