- Serum creatinine =< 1.5 X upper limit of normal (ULN) OR measured or calculated creatinine clearance (glomerular filtration rate [GFR] can also be used in place of creatinine or CrCl) >= 40 mL/min for subject with creatinine levels > 1.5 X institutional ULN; creatinine clearance should be calculated by Cockcroft-Gault