GFR

The Cockcroft-Gault equation estimates creatinine clearance (CrCl) as a surrogate for glomerular filtration rate (GFR). It accounts for age, weight, sex, and serum creatinine to estimate kidney function. This formula is widely used for drug dosing adjustments in patients with renal impairment.

• Remember: Female sex factor is 0.85 (women have less muscle mass → less creatinine production)
• Creatinine is in the denominator → higher Cr = lower GFR (inverse relationship)
• Age is subtracted from 140 → GFR naturally declines with age
• For drug dosing, Cockcroft-Gault is still the standard despite newer equations
• A GFR <60 for >3 months = Chronic Kidney Disease by definition

• Drug dosing: Most medication package inserts use Cockcroft-Gault for renal dose adjustments
• Screening for CKD: Quick bedside estimate of kidney function
• Monitoring progression: Track changes in kidney function over time
• Pre-operative assessment: Evaluate renal function before surgery or contrast administration