Urine Creatinine Clearance Calculator

Creatinine Clearance Formula:

\[ CrCl = \frac{(U_{cr} \times Volume_{mL})}{(P_{cr} \times Time_{min})} \]

Urine Creatinine (U_cr):

mg/dL

Urine Volume:

Plasma Creatinine (P_cr):

mg/dL

Collection Time:

minutes

Creatinine Clearance (CrCl):

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1. What Is Urine Creatinine Clearance?

Urine creatinine clearance measures the rate at which creatinine is cleared from the blood by the kidneys. It provides a direct assessment of glomerular filtration rate (GFR) and is considered more accurate than estimated GFR equations for certain clinical situations.

2. How Does The Calculator Work?

The calculator uses the creatinine clearance formula:

\[ CrCl = \frac{(U_{cr} \times Volume_{mL})}{(P_{cr} \times Time_{min})} \]

Where:

\( U_{cr} \) — Urine creatinine concentration (mg/dL)
\( Volume_{mL} \) — Total urine volume collected (mL)
\( P_{cr} \) — Plasma creatinine concentration (mg/dL)
\( Time_{min} \) — Collection time in minutes

Explanation: This formula calculates the volume of plasma cleared of creatinine per minute, providing a direct measure of kidney function.

3. Importance Of Creatinine Clearance Calculation

Details: 24-hour urine creatinine clearance is considered the gold standard for GFR measurement in clinical practice. It's essential for accurate assessment of kidney function, especially when serum creatinine-based estimates may be unreliable.

4. Using The Calculator

Tips: Enter urine creatinine in mg/dL, total urine volume in mL, plasma creatinine in mg/dL, and collection time in minutes. For 24-hour collections, use 1440 minutes. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why Use 24-Hour Urine Collection?
A: 24-hour collection accounts for diurnal variations in creatinine excretion and provides the most accurate measurement of true GFR.

Q2: What Are Normal Creatinine Clearance Values?
A: Normal range is typically 90-120 mL/min for young adults, decreasing with age. Values below 60 mL/min may indicate impaired kidney function.

Q3: How To Ensure Accurate Collection?
A: Start with empty bladder, collect all urine for 24 hours, keep sample refrigerated, and record exact start and end times.

Q4: When Is Urine Clearance Preferred Over eGFR?
A: In elderly, amputees, extremes of body size, pregnant women, and when precise GFR measurement is critical for medication dosing.

Q5: What Factors Affect Creatinine Clearance Accuracy?
A: Incomplete urine collection, meat consumption, exercise, medications, and muscle mass can all affect results.