Calculate Creatinine Clearance Equation

Creatinine Clearance Equation:

\[ CrCl = \frac{(140 - Age) \times Weight}{72 \times SCr} \times (0.85 \text{ if female}) \]

Age:

years

Weight:

Serum Creatinine (SCr):

mg/dL

Gender:

Creatinine Clearance (CrCl):

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1. What is Creatinine Clearance?

Creatinine clearance is a measure of the glomerular filtration rate (GFR) that estimates how well the kidneys are filtering creatinine from the blood. It provides an important assessment of renal function and is commonly used in clinical practice.

2. How Does the Calculator Work?

The calculator uses the standard creatinine clearance equation:

\[ CrCl = \frac{(140 - Age) \times Weight}{72 \times SCr} \times (0.85 \text{ if female}) \]

Where:

\( CrCl \) — Creatinine clearance (mL/min)
\( Age \) — Age in years
\( Weight \) — Body weight in kilograms
\( SCr \) — Serum creatinine (mg/dL)
0.85 — Female adjustment factor

Explanation: This equation estimates the rate at which creatinine is cleared from the blood by the kidneys, providing an approximation of renal function.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance is crucial for assessing kidney function, guiding drug dosing (especially for renally excreted medications), monitoring kidney disease progression, and evaluating overall renal health.

4. Using the Calculator

Tips: Enter age in years, weight in kilograms, serum creatinine in mg/dL, and select gender. All values must be valid (age between 1-120, weight > 0, creatinine > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between creatinine clearance and eGFR?
A: Creatinine clearance estimates actual clearance rate, while eGFR estimates glomerular filtration rate standardized to body surface area. Both assess kidney function but use different calculations.

Q2: What are normal creatinine clearance values?
A: Normal values are typically 90-120 mL/min for young adults, decreasing with age. Values below 60 mL/min may indicate impaired kidney function.

Q3: When is 24-hour urine collection needed?
A: For precise measurement, 24-hour urine collection with serum creatinine provides the most accurate creatinine clearance calculation.

Q4: What factors affect creatinine clearance?
A: Age, muscle mass, diet, medications, hydration status, and underlying medical conditions can all influence creatinine clearance values.

Q5: How often should creatinine clearance be monitored?
A: Frequency depends on clinical context - for stable patients annually, for those with kidney disease or on nephrotoxic drugs more frequently.