What are universal donors and universal recipients concerning the ABO blood system?
The Universals donors of the ABO blood type system are the individuals of the type O. The Type O blood doesn't have antigen A neither antigen B in its red blood cells and can be donated to individuals of any ABO type.
The Universal recipients of the ABO blood type system are the individuals of the type AB. The Type AB blood does not contain antibody anti-A neither antibody anti-B and people of this group can receive blood from any of the ABO types.