1. What is GFR from Urine Creatinine?

The GFR (Glomerular Filtration Rate) calculated from urine creatinine provides an estimate of kidney function by measuring how much creatinine is cleared from the blood into the urine over a specific time period.

2. How Does the Calculator Work?

The calculator uses the following equation:

Where:

• \( UCr \) — Urine creatinine concentration (mg/dL)
• \( V \) — Urine flow rate (mL/min)
• \( PCr \) — Plasma creatinine concentration (mg/dL)

Explanation: This calculation estimates how much plasma is cleared of creatinine per minute by the kidneys.

3. Importance of GFR Calculation

Details: Measuring GFR from urine creatinine provides a more direct assessment of kidney function than estimation equations, especially in patients with non-steady-state conditions or unusual muscle mass.

4. Using the Calculator

Tips: Enter urine creatinine in mg/dL, urine flow rate in mL/min, and plasma creatinine in mg/dL. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: When is this method preferred over estimation equations?
A: This method is preferred when precise measurement is needed, in patients with rapidly changing kidney function, or when estimation equations may be inaccurate.

Q2: How is urine flow rate (V) determined?
A: Urine flow rate is calculated from timed urine collections (e.g., 24-hour collection) by dividing total volume by collection time in minutes.

Q3: What are potential sources of error?
A: Incomplete urine collection, improper timing, and variations in creatinine metabolism can affect accuracy.

Q4: How does this compare to inulin clearance?
A: While inulin clearance is the gold standard, creatinine clearance provides a practical alternative that correlates well in most clinical situations.

Q5: Should patients prepare specially for this test?
A: Patients should avoid strenuous exercise before testing and follow instructions for proper urine collection.