The Cockcroft–Gault equation is a legacy formula that estimates creatinine clearance (CrCl) in mL/min from serum creatinine, age and body weight, with a 15% reduction applied for females.

Aspect	Detail
Derivation cohort	The original Cockcroft-Gault paper used data from 249 adult male inpatients aged 18–92 years, relating serum creatinine, age and body weight to 24-hour measured creatinine clearance.
Original performance	In a separate group of 236 patients, predicted creatinine clearance showed good correlation with the mean of two 24-hour clearances (correlation coefficient around 0.83).
Modern guideline position	The KDIGO 2024 guideline favours race-free CKD-EPI–based eGFR equations for CKD evaluation and most drug dosing. Cockcroft–Gault persists mainly where legacy pharmacokinetic studies or product information specify creatinine clearance cut-offs.
Assay and population limitations	The equation was derived before creatinine assay standardisation, in men only, with no Black participants. When used with modern standardised creatinine it tends to overestimate GFR and can lead to higher than intended doses for drugs with a narrow therapeutic index.

Practical scope

Adults (≥18 years) with relatively stable serum creatinine.
Situations where Cockcroft-Gault creatinine clearance is specifically required by a drug label, protocol or prior study.

When to avoid or interpret cautiously

Not for CKD staging. Prefer creatinine- or cystatin C-based eGFR equations for diagnosis and routine risk stratification.
Avoid in pregnancy, acute kidney injury, rapidly changing creatinine or markedly abnormal muscle mass. Consider nephrology input, measured GFR or cystatin C-based eGFR in these settings.
Use caution at extremes of body size (obesity, oedema, cachexia or amputations), where weight choice can materially change the result and eGFR-based or measured GFR approaches may be more reliable for critical decisions.

Creatinine Clearance (Cockcroft-Gault Equation)