- Alkaline phosphatase and AST may not both be > the ULN; for example, if the alkaline phosphatase is > the ULN but =< 2.5 x ULN, the AST must be =< the ULN; if the AST is > the ULN but =< 1.5 x ULN, the alkaline phosphatase must be =< ULN; Note: If alanine aminotransferase (ALT) is performed instead of AST (per institution's standard practice), the ALT value must be =< 1.5 x ULN; if both were performed, the AST must be =< 1.5 x ULN