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

Explanation: The equation estimates creatinine clearance based on age, weight, serum creatinine, and adjusts for gender differences in muscle mass.

3. Importance of CrCl Calculation

Details: CrCl estimation is crucial for medication dosing, particularly for drugs that are renally excreted. It helps prevent drug toxicity in patients with impaired kidney function.

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 Cockcroft-Gault rather than eGFR equations.

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

Q3: When should creatinine be measured?
A: Morning fasting sample is ideal, but random samples are acceptable. Avoid testing after meat-heavy meals or vigorous exercise.

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

Q5: Should actual body weight or ideal body weight be used?
A: For obese patients, some protocols recommend using adjusted body weight or ideal body weight.