The Cockcroft-Gault equation estimates creatinine clearance (CrCl) from serum creatinine, age, weight, and sex. It remains the standard method for drug dose adjustments in patients with renal impairment, especially in pharmacokinetic studies.
Formula
CrCl (mL/min) = [(140 − Age) × Weight × (0.85 if Female)] / (72 × Serum Creatinine)
Inputs Required
- Age in years
- Weight in kg or lb (use ideal or adjusted body weight in obese patients)
- Serum Creatinine in mg/dL or μmol/L
- Sex (multiplier of 0.85 for females)
Interpretation (CKD Staging)
- ≥90 mL/min — Normal kidney function
- 60–89 mL/min — Mild impairment (Stage 2)
- 30–59 mL/min — Moderate impairment (Stage 3)
- 15–29 mL/min — Severe impairment (Stage 4)
- <15 mL/min — Kidney failure (Stage 5)
Clinical Notes
Cockcroft-Gault tends to overestimate GFR in obese patients. For drug dose adjustments, FDA labeling typically references this equation rather than CKD-EPI or MDRD. Always interpret in clinical context.