1. What is the Cockcroft-Gault Equation?

The Cockcroft-Gault equation estimates creatinine clearance (CrCl), which approximates glomerular filtration rate (GFR). It's 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 in mg/dL
• 0.85 — Adjustment factor for females

Explanation: The equation estimates how quickly creatinine is cleared from the blood, which correlates with kidney function.

3. Importance of CrCl Calculation

Details: CrCl estimation is essential for adjusting medication dosages in patients with impaired kidney function to prevent toxicity or underdosing.

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 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 90-120 mL/min for young adults, decreasing with age. Below 60 may indicate impaired kidney function.

Q3: Should actual or ideal body weight be used?
A: For obese patients, some protocols recommend using adjusted body weight or ideal body weight - consult specific guidelines.

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

Q5: When is measured CrCl preferred?
A: For critical medications or when precise dosing is needed, 24-hour urine collection for measured CrCl may be preferred.