1. What is Net Filtration Rate (GFR)?

Definition: Glomerular Filtration Rate (GFR) measures how much blood passes through the glomeruli (tiny filters in the kidneys) each minute.

Purpose: It's a key indicator of kidney function and helps diagnose and monitor kidney disease.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( GFR \) — Glomerular Filtration Rate (mL/min)
• \( U \) — Urine concentration of the substance (mg/mL)
• \( V \) — Urine flow rate (mL/min)
• \( P \) — Plasma concentration of the substance (mg/mL)

Explanation: The formula calculates how efficiently the kidneys are filtering waste from the blood.

3. Importance of GFR Measurement

Details: GFR helps assess kidney function, stage chronic kidney disease, and determine appropriate medication dosages.

4. Using the Calculator

Tips: Enter the urine concentration (U), urine flow rate (V), and plasma concentration (P). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What substances are typically used to measure GFR?
A: Inulin is the gold standard, but creatinine is commonly used in clinical practice.

Q2: What's a normal GFR value?
A: Normal is about 90-120 mL/min/1.73m². Values below 60 for 3+ months indicate chronic kidney disease.

Q3: How is urine flow rate (V) measured?
A: Typically by collecting all urine for 24 hours and calculating the per-minute rate.

Q4: Why is plasma concentration (P) needed?
A: It provides the baseline concentration to compare against what's filtered by the kidneys.

Q5: How accurate is this calculation?
A: Very accurate when using proper measurement techniques, though clinical estimates often use simpler formulas.