1. What is the Cockcroft-Gault Formula?

The Cockcroft-Gault formula estimates creatinine clearance (CrCl) from serum creatinine, age, weight, and gender. It is widely used for drug dosing adjustments in patients with renal impairment and for assessing kidney function.

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault formula:

Where:

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

Explanation: The formula estimates the rate at which creatinine is cleared from the blood by the kidneys, providing an approximation of glomerular filtration rate.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance is essential for determining appropriate drug dosages for medications that are eliminated by the kidneys, assessing renal function, and monitoring kidney disease progression.

4. Using the Calculator

Tips: Enter age in years, weight in kilograms, 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 formula?
A: It is one of the most widely used and validated formulas for estimating creatinine clearance, particularly for drug dosing adjustments.

Q2: What are normal CrCl values?
A: Normal CrCl is approximately 95-125 mL/min for men and 85-115 mL/min for women. Values below these ranges may indicate renal impairment.

Q3: When should creatinine clearance be measured?
A: When prescribing nephrotoxic drugs, in elderly patients, or when monitoring patients with known or suspected kidney disease.

Q4: Are there limitations to this formula?
A: Less accurate in extremes of age, obesity, malnutrition, rapidly changing renal function, and in patients with unstable creatinine levels.

Q5: Should ideal body weight be used?
A: For obese patients, some clinicians use ideal body weight rather than actual weight for more accurate estimation.