1. What is Creatinine Clearance?

Creatinine clearance (CrCl) is a measure of the glomerular filtration rate (GFR) that estimates how well the kidneys are filtering creatinine from the blood. It's commonly used to assess kidney function and adjust medication dosages.

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault equation:

Where:

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

Example: Age 50 years, Weight 70 kg, SCr 1 mg/dL, Male gender:
CrCl = (140 - 50) × 70 / (72 × 1) = 90 × 70 / 72 = 87.5 mL/min

3. Importance of CrCl Calculation

Details: Creatinine clearance is essential for drug dosing adjustments in patients with renal impairment, monitoring kidney function over time, and assessing the severity of kidney disease.

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 positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between CrCl and eGFR?
A: CrCl estimates creatinine clearance using the Cockcroft-Gault equation, while eGFR estimates glomerular filtration rate using equations like CKD-EPI or MDRD.

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

Q3: When is CrCl preferred over eGFR?
A: CrCl is often preferred for drug dosing adjustments, especially for medications with narrow therapeutic windows.

Q4: What are the limitations of the Cockcroft-Gault equation?
A: Less accurate in elderly, obese, malnourished patients, and those with unstable renal function or extreme body weights.

Q5: Should ideal body weight be used?
A: For obese patients (BMI >30), some guidelines recommend using ideal body weight rather than actual body weight in the calculation.