Genotypes Blood Types Agglutinogens Agglutinins OO O − Anti
-A and Anti-B OA or AA A A Anti-B OB or BB B B Anti-A AB AB A
and B −
observed under a microscope. If the red blood cells have become clumped—that is,
―agglutinated‖—one knows that an antibody-antigen reaction has resulted. Table 35-2 lists the
presence (+) or absence (−) of agglutination of the four types of red blood cells. Type O red blood cells
have no agglutinogens and therefore do not react with either the anti-A or the anti-B agglutinins. Type
A blood has A agglutinogens and therefore agglutinates with anti-A agglutinins. Type B blood has B
agglutinogens and agglutinates with anti-B agglutinins. Type AB blood has both A and B
agglutinogens and agglutinates with both types of agglutinins.
