What is the ABO blood group system?

Published On: Sep 12 2012 10:31:40 AM CDT   Updated On: Sep 26 2012 02:08:44 PM CDT

The ABO blood group system consists of four major blood groups. According to the American Red Cross, these groups are based on the presence or absence of A and B on the surface of red blood cells.

 

The American Red Cross breaks down the groups as:

 

Group A: having only an A antigen on red cells (also has a B antibody in the plasma)

Group B: having only a B antigen on red cells (also has an A antibody in the plasma)

Group AB: having both A and B antigens on red cells (also has neither A nor B antibodies in the plasma)

Group O: having neither A nor B antigens on red cells (also has both A and B antibodies in the plasma)