Creatinine Clearance

Cockcroft-Gault remains the reference for drug dosing, because most renal dosing guidance was derived using it — eGFR from CKD-EPI is not interchangeable for that purpose, particularly at extremes of body size. Which weight to enter matters: use actual body weight normally, ideal body weight if obese, and adjusted body weight in significant obesity. The equation assumes stablerenal function and is invalid in acute kidney injury, where creatinine lags behind real clearance. It also overestimates in muscle wasting, amputation and advanced age.