1. What is the Cockcroft-Gault Equation?

The Cockcroft-Gault equation estimates creatinine clearance (CrCl), which approximates glomerular filtration rate (GFR). It was developed in 1973 and is commonly used for drug dosing adjustments in patients with kidney impairment.

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault equation:

Where:

• \( Age \) — Age in years
• \( Weight \) — Body weight in kilograms
• \( SCr \) — Serum creatinine (mg/dL)
• 0.85 — Female adjustment factor

Explanation: The equation accounts for age-related decline in kidney function and differences in creatinine production between genders.

3. Importance of GFR Calculation

Details: While newer equations exist, Cockcroft-Gault remains widely used for medication dosing, particularly for drugs with narrow therapeutic windows that are renally excreted.

4. Using the Calculator

Tips: Enter age in years, weight in kg, serum creatinine in mg/dL, and select gender. All values must be valid (age 1-120, weight > 0, SCr > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why use Cockcroft-Gault instead of CKD-EPI?
A: Cockcroft-Gault is still preferred for drug dosing as many pharmacokinetic studies used this equation. CKD-EPI is better for CKD staging.

Q2: What about obese patients?
A: For obese patients, ideal body weight or adjusted body weight may be used instead of actual weight.

Q3: How accurate is this equation?
A: It tends to overestimate GFR in elderly and malnourished patients with low muscle mass.

Q4: Should this be used for all patients?
A: Caution is needed in extremes of age, weight, muscle mass, and in patients with rapidly changing kidney function.

Q5: What are normal values?
A: Normal CrCl is approximately 95-125 mL/min for young men and 85-115 mL/min for young women.