ABO Blood Group Reactivity blood group genotypes antigens a antibodies to (phenotype) ABO in serum A AA,AO A anti-B B BB,BO B anti-A AB AB A and B none 0 00 H anti-A/BABO Blood Group Reactivity blood group genotypes antigens antibodies to (phenotype) ABO in serum A AA, AO A anti-B B BB, BO B anti-A AB AB A and B none O OO H anti-A/B