Human blood can contain the A antigen the Ba the A and B antigens or neither antigen A third called the Rh antigen is important in human rep and again may or may not be present in an indiv is called type A positive if the individual has the but not the B antigen A person having only the antigens is said to have type AB negative blood having only the Rh antigen has type O positive blood types are defined in a similar manner Ide blood types of the individuals in regions a thro the right