AB형, or blood type AB, is one of the four main blood types in the ABO blood group system. It is characterized by the presence of both A and B antigens on the surface of red blood cells. Individuals with this blood type can receive blood from all other types, making them universal recipients. People with AB형 blood are often considered to have a unique personality, as they are thought to be a blend of the traits associated with both A형 and B형 blood types. This combination can lead to a balanced and adaptable nature, but scientific evidence supporting these personality traits is limited.