1. What is the Cockcroft-Gault Formula?

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

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault formula:

Where:

• \( Age \) — Age in years
• \( IBW \) — Ideal body weight in kg
• \( SCr \) — Serum creatinine (mg/dL)
• 0.85 — Female multiplier

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

3. Importance of CrCl Calculation

Details: Creatinine clearance is crucial for adjusting medication dosages in patients with impaired kidney function to avoid toxicity or underdosing.

4. Using the Calculator

Tips: Enter age in years, ideal body 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 ideal body weight instead of actual weight?
A: IBW is used to avoid overestimating CrCl in obese patients, as creatinine is produced by muscle mass which doesn't increase proportionally with fat.

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

Q3: When should this formula not be used?
A: Not recommended for children, elderly with low muscle mass, amputees, or those with rapidly changing kidney function.

Q4: How does this compare to eGFR?
A: CrCl tends to be higher than eGFR as it estimates actual clearance rather than normalizing to body surface area.

Q5: Why is there a gender adjustment?
A: Women typically have less muscle mass than men, resulting in lower creatinine production and clearance.