Calculator Creatinine Clearance Calculator

Cockcroft-Gault Equation:

\[ CrCl = \frac{(140 - Age) \times Weight}{72 \times SCr} \times Gender \]

Age:

years

Weight:

Serum Creatinine (SCr):

mg/dL

Gender:

Creatinine Clearance (CrCl):

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1. What is the Cockcroft-Gault Equation?

The Cockcroft-Gault equation estimates creatinine clearance (CrCl) from serum creatinine, age, weight, and gender. It is widely used for drug dosing adjustments in patients with renal impairment and for assessing kidney function.

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault equation:

\[ CrCl = \frac{(140 - Age) \times Weight}{72 \times SCr} \times Gender \]

Where:

\( CrCl \) — Creatinine clearance (mL/min)
\( Age \) — Age in years
\( Weight \) — Body weight in kilograms
\( SCr \) — Serum creatinine (mg/dL)
\( Gender \) — 1.0 for male, 0.85 for female

Explanation: The equation estimates the rate at which creatinine is cleared from the blood by the kidneys, providing an approximation of glomerular filtration rate.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance is essential for drug dosing adjustments, particularly for medications with narrow therapeutic windows that are primarily eliminated by the kidneys. It helps prevent toxicity in patients with impaired renal function.

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 CrCl and eGFR?
A: CrCl estimates creatinine clearance specifically, 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 young adults, decreasing with age. Values below 60 mL/min indicate renal impairment.

Q3: When should I use ideal body weight vs actual body weight?
A: For obese patients (BMI > 30), ideal body weight is often recommended. For normal or underweight patients, actual body weight should be used.

Q4: Are there limitations to the Cockcroft-Gault equation?
A: Yes, it may overestimate CrCl in elderly patients, malnourished individuals, and those with unstable creatinine levels. It's less accurate at extremes of age and body size.

Q5: Can this calculator be used for pediatric patients?
A: No, the Cockcroft-Gault equation is validated for adults only. Pediatric patients require different equations and considerations.