- Estimated creatinine clearance of > 30 mL/min/1.73m², calculated using the Cockcroft-Gault formula, or serum creatinine < 2.5 mg/dL [Cockcroft-Gault formula: creatinine clearance = (140 - age) x weight in kg divided by (72 x serum creatinine in mg/dL); multiply result by 0.85 for females]