Rarest Blood Type in the World: According to Stanford Blood Centre, there are a total of 8 types of blood groups, which are categorised based on the presence or absence of certain antigens on the ...
You are probably aware of the two main blood group systems: the AB system and the rhesus system. Under the AB system, there are four main blood types A, B, AB and O. And each of these four types can ...
A person's blood type is determined by "the presence or absence of certain antigens – substances that can trigger an immune response if they are foreign to the body," according to American Red Cross.