Creatinine Clearance (Cockcroft-Gault)
Estimate creatinine clearance (CrCl) — a measure of kidney function — using the Cockcroft-Gault equation. Essential for drug dosing in patients with renal impairment.
Creatinine Clearance (Cockcroft-Gault)
intermediateEstimate creatinine clearance for renal function assessment
Formula
CrCl = [(140-age)×wt]/(72×Cr) × 0.85 if female
How It Works
The Cockcroft-Gault equation estimates creatinine clearance based on serum creatinine, age, weight, and sex:
CrCl (mL/min) = ((140 − Age) × Weight) / (72 × Serum Cr)
For females: multiply result by 0.85
Interpretation: Normal CrCl: 90-120 mL/min. Mild impairment: 60-89. Moderate: 30-59. Severe: 15-29. Kidney failure: <15.
Example
A 50-year-old man weighing 70 kg with serum creatinine 1.0 mg/dL:
CrCl = ((140-50) × 70) / (72 × 1.0)
CrCl = (90 × 70) / 72 = 87.5 mL/min
This indicates mildly reduced kidney function (Stage 2 CKD).
Frequently Asked Questions
What is the difference between CrCl and eGFR?
Both estimate kidney function. CrCl (Cockcroft-Gault) overestimates GFR slightly and is still widely used for drug dosing. eGFR (MDRD/CKD-EPI) is more accurate for chronic kidney disease staging.
When should I adjust drug doses based on CrCl?
Many drugs require dose adjustment when CrCl falls below 50 mL/min, especially renally eliminated drugs (antibiotics, antidiabetics, anticoagulants). Always consult drug-specific guidelines.