Creatinine Clearance Calculator Kidney

Creatinine Clearance Formula:

\[ CrCl = \frac{U_{cr} \times V}{P_{cr} \times t} \]

Urine Creatinine (U_cr):

mg/dL

Urine Volume (V):

Plasma Creatinine (P_cr):

mg/dL

Collection Time (t):

min

Creatinine Clearance (CrCl):

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1. What is Creatinine Clearance?

Creatinine clearance is a measure of kidney function that estimates the rate at which creatinine is cleared from the blood by the kidneys. It provides a more accurate assessment of glomerular filtration rate (GFR) than serum creatinine alone, especially when using 24-hour urine collection.

2. How Does the Calculator Work?

The calculator uses the creatinine clearance formula:

\[ CrCl = \frac{U_{cr} \times V}{P_{cr} \times t} \]

Where:

\( U_{cr} \) — Urine creatinine concentration (mg/dL)
\( V \) — Urine volume (mL)
\( P_{cr} \) — Plasma creatinine concentration (mg/dL)
\( t \) — Collection time (minutes)

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

3. Importance of Creatinine Clearance

Details: Creatinine clearance is crucial for assessing renal function, diagnosing kidney disease stages, adjusting medication dosages for renally excreted drugs, and monitoring kidney function in various clinical conditions.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between CrCl and eGFR?
A: CrCl is measured using urine collection, while eGFR is estimated from serum creatinine using equations. CrCl is generally more accurate but requires urine collection.

Q2: What are normal creatinine clearance values?
A: Normal values are approximately 95-125 mL/min for men and 85-115 mL/min for women, decreasing with age.

Q3: How should 24-hour urine be collected?
A: Discard first morning urine, then collect all urine for next 24 hours, including first morning urine of next day. Record exact collection time.

Q4: What factors affect creatinine clearance?
A: Age, muscle mass, diet, medications, hydration status, and kidney function can all influence creatinine clearance results.

Q5: When is creatinine clearance preferred over eGFR?
A: In patients with extremes of age or muscle mass, amputees, pregnant women, and for precise drug dosing of nephrotoxic medications.