1. What is GFR from Creatinine Clearance?

GFR (Glomerular Filtration Rate) can be estimated from creatinine clearance (CrCl) by adjusting for body surface area (BSA). This provides a standardized measure of kidney function that can be compared across individuals of different sizes.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( CrCl \) — Creatinine clearance (mL/min)
• \( BSA \) — Body surface area (m²)
• 1.73 — Standard adult body surface area (m²)

Explanation: The equation adjusts the measured creatinine clearance to what it would be if the person had a standard body size of 1.73 m².

3. Importance of GFR Calculation

Details: Standardized GFR allows for accurate assessment of kidney function across patients of different body sizes and is essential for diagnosing and staging chronic kidney disease.

4. Using the Calculator

Tips: Enter creatinine clearance in mL/min and body surface area in m². Both values must be greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: Why adjust CrCl for body surface area?
A: Kidney function is proportional to body size. Adjustment allows comparison of kidney function between individuals of different sizes.

Q2: How is body surface area calculated?
A: BSA can be estimated using formulas like Du Bois or Mosteller, based on height and weight.

Q3: What's the difference between CrCl and GFR?
A: CrCl is the actual measured value, while GFR is the CrCl adjusted to standard body size (1.73 m²).

Q4: When is this calculation most useful?
A: When you have a measured creatinine clearance (e.g., from 24-hour urine collection) and want to report standardized GFR.

Q5: What are normal GFR values?
A: Normal is generally ≥90 mL/min/1.73m², though values decline with age. Below 60 for 3+ months indicates CKD.