There are various blood typing card based on the presence/absence of inherited antigen on the surface of erythrocytes, AOB and Rh being the most popular ones.

The AOB system is related to the immunoglobulins anti-A and anti-B, produced during the first years of life. Presence/absence of certain glycolipids in erythrocyte membrane determines the A, B, AB, and O blood groups.

The Rhesus system is suffixed to the ABO system. Although there are about 30 different antigens in this group, the common blood tests focus only on antigen-D. Rh test shows whether an individual has (Rh positive) or does not have (Rh negative) the 'Rhesus factor', or antigen-D, expressed by a transmembrane protein.

ABO system:

Rh system: