1. What is the Cockcroft-Gault Equation?

The Cockcroft-Gault equation estimates creatinine clearance (CrCl) from serum creatinine, age, weight, and sex. 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 which correlates with glomerular filtration rate (GFR), accounting for age-related decline in kidney function and gender differences.

3. Importance of CrCl Calculation

Details: CrCl estimation is crucial for medication dosing adjustments, particularly for drugs that are renally excreted or nephrotoxic.

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 CKD-EPI?
A: Cockcroft-Gault estimates creatinine clearance (CrCl) rather than GFR, and is still widely used for drug dosing calculations.

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, declining 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, pregnant women, and those with rapidly changing kidney function.

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