1. What is the Cockcroft-Gault Formula?

The Cockcroft-Gault formula 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
• \( Weight \) — Body weight in kg
• \( SCr \) — Serum creatinine (mg/dL)
• 0.85 — Adjustment factor for females

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

3. Importance of CrCl Calculation

Details: Creatinine clearance is important for adjusting medication dosages in patients with impaired kidney function to prevent drug 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: Cockcroft-Gault is still widely used for drug dosing, though some guidelines now recommend using CKD-EPI or MDRD equations.

Q2: What are normal CrCl values?
A: Normal is typically 90-120 mL/min for young adults, decreasing with age. Below 60 mL/min indicates impaired kidney function.

Q3: Should actual or ideal body weight be used?
A: For obese patients, some protocols recommend using ideal body weight or adjusted body weight rather than actual weight.

Q4: Are there limitations to this formula?
A: Less accurate in elderly, malnourished patients, amputees, and those with rapidly changing kidney function or extremely high/low muscle mass.

Q5: How often should CrCl be recalculated?
A: Should be reassessed whenever kidney function may have changed significantly or when adjusting medications that are renally cleared.