Clcreat (ml/min) = (140-age [yr]) x body wt [kg] 72 x serum creatinine [mg/dl] For females: multiply creatinine clearance by a factor of 0.85. OR Clcreat (ml/min) = (140-age [yr]) x body wt [kg] serum creatinine [µmol/L] K=1.05 for females K=1.23 for males