Cockcroft-Gault

Creatinine clearance (mL/min), not eGFR

Creatinine clearance estimate from serum creatinine in adults

Biomarkers
Creatinine
Validated for
Adults (no age range declared)
Inputs
Age, Sex, Creatinine, Weight
Reports
mL/min
Published
1976

The eGFR guide explains how creatinine clearance relates to indexed and absolute GFR.

Formula

CrCl=(140−age)×weight×(0.85 if female)72×Scr\text{CrCl} = \frac{(140 - \text{age}) \times \text{weight} \times (0.85 \text{ if female})}{72 \times S_{cr}}

As text: CrCl = [(140-age) × weight × (0.85 if female)] / (72 × SCr)

Constants

SymbolMeaningValue
140Age subtraction constantyears
72Denominator constant
Sex factorSex-dependent multiplier
Female: 0.85
Male: 1.00
WeightActual body weight (input)kg
ScrS_{cr}Serum creatinine (input)mg/dL
AgePatient age (input)years

How it was developed

Derived from the relationship between age and 24-hour urine creatinine excretion per kg, measured in duplicate in 249 hospitalised men aged 18–92 at Queen Mary Veterans' Hospital, Montreal. Predictions were compared with the mean of two measured 24-hour creatinine clearances in 236 patients, 226 of whom were also in the derivation group.

Clinical notes

  • Not indexed to body surface area (1.73 m²)
  • Female factor 0.85 is a 15% reduction; other authors had proposed 10–20%
  • Built on Technicon N-11B creatinine, before creatinine assay standardization
  • Used in many past pharmacokinetic studies that underpin drug dosing

Limitations

  • Derived in adult men; not studied in women or children
  • Overestimates GFR in reduced kidney function or heavy proteinuria (creatinine secretion)
  • Needs stable creatinine; overestimates early in acute kidney failure
  • Overestimates clearance with muscle wasting, marked obesity or ascites

References

  1. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41. doi:10.1159/000180580

Related equations