1. What is the Cockcroft-Gault Formula?

The Cockcroft-Gault formula estimates creatinine clearance (CrCl) from serum creatinine, age, weight, and sex. It is commonly used for drug dosing adjustments in patients with kidney impairment.

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault formula:

Where:

• \( Scr \) — Serum creatinine (mg/dL)
• \( age \) — Age in years
• \( weight \) — Weight in kilograms
• 0.85 — Female multiplier

Explanation: The equation estimates the rate at which creatinine is cleared from the blood by the kidneys.

3. Importance of CrCl Calculation

Details: CrCl estimation is crucial for adjusting medication dosages in patients with kidney impairment, particularly for drugs with narrow therapeutic windows.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: Why use Cockcroft-Gault instead of eGFR?
A: Many drug dosing guidelines specifically reference CrCl from Cockcroft-Gault rather than eGFR from other equations.

Q2: What are normal CrCl values?
A: Normal is approximately 95-125 mL/min for young men and 85-115 mL/min for young women, decreasing with age.

Q3: Should ideal body weight be used?
A: For obese patients, some clinicians use adjusted body weight or ideal body weight, though practices vary.

Q4: Are there limitations to this formula?
A: Less accurate in extremes of age/weight, amputees, pregnant women, and those with rapidly changing kidney function.

Q5: Is this suitable for all medications?
A: While widely used, some drugs may require more precise GFR measurement for dosing.