Formula: CrCl (mL/min) = [(140 - age) x weight(kg)] / (72 x SCr mg/dL), multiplied by 0.85 for females.
Weight logic: if actual body weight (ABW) is less than ideal body weight (IBW), ABW is used. If ABW is greater than IBW, an adjusted body weight is used: AdjBW = IBW + 0.4 x (ABW - IBW). Educational use only, verify with clinical judgment / institutional protocol.