1. What is the Cockcroft-Gault Formula?

The Cockcroft-Gault formula estimates creatinine clearance (CrCl) which correlates with glomerular filtration rate (GFR). 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 equation:

Where:

• \( age \) — Age in years
• \( weight \) — Weight in kilograms
• \( Scr \) — Serum creatinine (mg/dL)
• 0.85 — Adjustment factor for female gender

Explanation: The formula 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, particularly for drugs that are primarily excreted by the kidneys.

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, creatinine > 0).

5. Frequently Asked Questions (FAQ)

Q1: Why use Cockcroft-Gault instead of eGFR?
A: Many drug dosing guidelines are based on CrCl from Cockcroft-Gault rather than eGFR from other 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 formula?
A: Less accurate in extremes of body composition (obese, cachectic), elderly, and those with rapidly changing kidney function.

Q5: Should ideal body weight be used?
A: For obese patients (>30% over IBW), consider using adjusted body weight or ideal body weight in the calculation.