1. What is the Cockcroft-Gault Equation?

The Cockcroft-Gault equation estimates creatinine clearance (CrCl) which correlates with 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 kg
• \( Scr \) — Serum creatinine (mg/dL)
• 0.85 — Female multiplier

Explanation: The equation estimates creatinine clearance based on age, weight, serum creatinine, and gender.

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

5. Frequently Asked Questions (FAQ)

Q1: Why use Cockcroft-Gault instead of eGFR?
A: Many drug dosing guidelines specifically reference Cockcroft-Gault, though some are transitioning to CKD-EPI based dosing.

Q2: What are normal CrCl values?
A: Normal is approximately 90-120 mL/min for young adults, decreasing with age.

Q3: Should ideal or actual body weight be used?
A: For obese patients, consider using ideal body weight or adjusted body weight. Consult specific drug guidelines.

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

Q5: How often should CrCl be recalculated?
A: With significant changes in clinical status, weight, or creatinine (typically daily in hospitalized patients).