ABO‐Nonidentical Liver Transplantation in the United States

Under the United Network for Organ Sharing (UNOS) policy, deceased donor livers may be offered to ABO‐nonidentical candidates at each given Model for End‐Stage Liver Disease (MELD) score and to blood type B candidates at MELD ≥30. To evaluate ABO‐nonidentical liver transplantation (LT) in the United States, we examined all adult LT non–status 1 candidates, recipients and deceased liver donors from 2013 to 2015. There were 34 920 LT candidates (47% type O, 38% type A, 12% type B, 3% type AB) and 10 479 deceased liver donors (47% type O, 38% type A, 12% type B, 3% type AB). ABO‐nonidentical LT occurred in 2%, 3%, 20% and 36% of types O, A, B and AB recipients, respectively, which led to a net liver loss of 6% for type O and 2% for type A recipients but a net liver gain of 14% for type B and 55% for type AB recipients. The LT MELD scores of ABO‐identical versus ‐nonidentical recipients were 29 versus 34 for type O, 29 versus 19 for type A, 25 versus 38 for type B, and 22 versus 28 for type AB (p < 0.01). ABO‐nonidentical LT increased liver supply for candidates with blood types B and AB but decreased supply for type O and A candidates. We urge refinement of UNOS policy surrounding ABO‐nonidentical LT.