1. What is Creatinine Clearance?

Creatinine clearance (CrCl) is a measure of the rate at which creatinine is cleared from the blood by the kidneys. It provides an estimate of glomerular filtration rate (GFR) and is 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: 70-year-old, 70kg male with SCr=1 mg/dL → CrCl ≈ 97 mL/min

3. Importance of CrCl Calculation

Details: Creatinine clearance is essential for drug dosing adjustments, particularly for medications that are renally eliminated. It helps prevent drug toxicity in patients with impaired kidney function.

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 formula, while eGFR estimates glomerular filtration rate using equations like CKD-EPI or MDRD.

Q2: When is CrCl preferred over eGFR?
A: CrCl is often preferred for drug dosing adjustments, particularly in elderly patients and those with extremes of body weight.

Q3: What are normal CrCl values?
A: Normal CrCl is approximately 95-105 mL/min for young adults, decreasing with age. Values below 60 mL/min indicate impaired kidney function.

Q4: Are there limitations to the Cockcroft-Gault formula?
A: Yes, it may overestimate CrCl in obese patients, elderly, and those with reduced muscle mass. It's less accurate in hospitalized patients.

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.