ABO System

The ABO System  is a CODED CLINICAL ENTRY.

The ABO System is a system of 4 basic types into which human blood may be classified according to the presence or absence of particular antigens.

The 4 types are:

• A - Blood group A has A antigens in its red blood cells and anti-B antibodies in its plasma;

• B - Blood group B has B antigens and anti-A antibodies in its plasma;

• O - Blood group O blood has no antigens but both anti-A and anti-B antibodies

• AB - Blood group AB has both A and B antigens but no antibodies, as it would destroy itself.

For further information on the ABO System, see the NHS website at: Blood groups.