Interpretation
| Result | Meaning |
|---|---|
| ≥ 90 | Normal |
| 60–89 | Mild impairment |
| 30–59 | Moderate impairment |
| 15–29 | Severe impairment |
| < 15 | Kidney failure |
Formula
CrCl (mL/min) = (140 − age) × weight (kg) ÷ (72 × Scr mg/dL) × 0.85 if female. SI: (140 − age) × weight × 1.23 ÷ Scr (µmol/L) [× 0.85 female]. IBW = 50 kg (M) / 45.5 kg (F) + 0.9055 × (height cm − 152.4). Adjusted BW = IBW + 0.4 × (actual − IBW).
Clinical pearls
- Not valid when creatinine is not at steady state (AKI) or with very low muscle mass (amputees, cachexia, elderly frail): it overestimates clearance.
- Weight choice changes the answer substantially in obesity; most pharmacy protocols use adjusted body weight when actual weight exceeds ~120% of IBW.
- The result is in mL/min (not indexed to 1.73 m²), which is what drug labels based on Cockcroft-Gault expect.
Examples
crcl 78 yo woman 60 kg creat 1.2cockcroft gault 65M 110kg 178cm cr 105 umol/Lwhat is the creatinine clearance for a 50 year old man weighing 80 kg with creatinine 1.0
FAQ
Should I use Cockcroft-Gault or eGFR for drug dosing?
Most drug labels were derived with Cockcroft-Gault, so pharmacists generally use CrCl for dosing; eGFR (CKD-EPI) is used to stage CKD.
Which weight should I use in Cockcroft-Gault?
Actual weight if at or below ideal body weight; in obesity (actual >120% IBW) adjusted body weight (IBW + 0.4 × excess) is the most common convention.