- Hepatic function: Serum conjugated (direct) bilirubin < 2 x upper limit of normal for age as per local laboratory and ALT and AST < 5 x upper limit of normal as per local laboratory. Patients with hyperbilirubinemia as a consequence of hyperhemolysis, or who experience a sudden, profound change in the serum hemoglobin after a RBC transfusion, are not excluded.