Calculator Creatinine Clearance Calculator

Cockcroft-Gault Formula:

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

Age:

years

Weight:

Serum Creatinine (SCr):

mg/dL

Gender:

Creatinine Clearance (CrCl):

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1. What is the Cockcroft-Gault Formula?

The Cockcroft-Gault formula is a widely used method for estimating creatinine clearance (CrCl), which approximates glomerular filtration rate (GFR). It's commonly used for drug dosing adjustments in patients with renal impairment.

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault formula:

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

Where:

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

Explanation: The formula estimates kidney function by accounting for age-related decline in renal function, body size, and gender differences in muscle mass.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance is crucial for drug dosing adjustments, assessing renal function, and monitoring patients with kidney disease. Many medications require dosage modifications based on CrCl values.

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 1-120, weight > 0, SCr > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between CrCl and eGFR?
A: CrCl estimates creatinine clearance while eGFR estimates glomerular filtration rate. CrCl is often used for drug dosing, while eGFR is used for CKD staging.

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

Q3: When is Cockcroft-Gault formula preferred?
A: It's commonly used for drug dosing adjustments, especially for medications with narrow therapeutic windows that are renally eliminated.

Q4: Are there limitations to this formula?
A: Less accurate in extremes of age, obesity, malnutrition, amputees, and patients with rapidly changing renal function.

Q5: Should ideal body weight be used?
A: For obese patients, some guidelines recommend using ideal body weight rather than actual body weight for more accurate estimation.