Why do we have different blood types?
Before we get to blood compatibility and the blood compatibility chart, we first need to understand why we have different blood types1 in the first place.
One factor that determines blood type is the antigens in a person’s blood. These are chemicals found in the blood that can trigger an immune response. These antigens are known as either antigen A or antigen B.
Type A blood means that antigen A can be found in the red blood cells, and antigen B is in the plasma of the blood. Type B, on the other hand, means that antigen B is in the red blood cells, and antigen A is in the plasma.
People can also have type AB blood, which means that their red blood cells both contain antigen A and antigen B, and none are present in plasma. The inverse of this is type O blood, wherein there are no antigens in the red blood cells, but the plasma has both antigen A and antigen B.
There is also a type of protein, known as the Rh factor, which is another factor when it comes to our blood types. The presence of the Rh factor is symbolized by a (+) symbol, and the absence of it by a (-) symbol.
When we combine the antigens and the Rh factor, we get a total of 8 common blood types. These are are: A+, A-, B+, B-, O+, O-, AB+, AB-.
People with blood type O are considered as universal red blood cell donors, while those with blood type AB are universal plasma donors. These blood types are highly in demand because of their compatibility with the other blood types. You can refer to the blood compatibility chart to see which are types are more compatible with other blood types.