1. What is eGFR to CrCl Conversion?

The eGFR to CrCl conversion adjusts the estimated glomerular filtration rate (eGFR) to creatinine clearance (CrCl) by accounting for individual body surface area (BSA). This is important for drug dosing where CrCl is specifically required.

2. How Does the Calculator Work?

The calculator uses the conversion formula:

Where:

• \( eGFR \) — Estimated glomerular filtration rate (mL/min/1.73m²)
• \( BSA \) — Body surface area (m²)
• 1.73 — Standard BSA value used in eGFR calculations

Explanation: The formula adjusts the standardized eGFR (normalized to 1.73m² BSA) to the patient's actual BSA.

3. Importance of CrCl Calculation

Details: While eGFR is used for kidney function assessment, many drug dosing guidelines (especially for antibiotics and chemotherapy) still use CrCl. This conversion helps bridge between these measures.

4. Using the Calculator

Tips: Enter eGFR in mL/min/1.73m² and BSA in m². Both values must be positive numbers. Common BSA ranges are 1.4-2.2 m² for adults.

5. Frequently Asked Questions (FAQ)

Q1: Why convert eGFR to CrCl?
A: Many medication dosing guidelines (especially older ones) are based on CrCl rather than eGFR. This conversion allows use of eGFR values in these guidelines.

Q2: How accurate is this conversion?
A: It provides a reasonable estimate but may not be as accurate as measured CrCl in all patients, particularly those with very high or low muscle mass.

Q3: When should I use actual CrCl measurement instead?
A: For critical medications with narrow therapeutic windows, or in patients with extreme body habitus (very obese or cachectic).

Q4: What's the difference between eGFR and CrCl?
A: eGFR estimates actual kidney function while CrCl measures creatinine elimination. They correlate but aren't identical due to creatinine's non-ideal filtration marker properties.

Q5: Can I use this for pediatric patients?
A: The formula works mathematically, but pediatric drug dosing often uses different approaches - consult pediatric references.