Cockcroft Gault Creatinine Clearance Calculator

Cockcroft-Gault Equation:

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

Age:

years

Weight:

Serum Creatinine (SCr):

mg/dL

Gender:

Creatinine Clearance (CrCl):

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1. What is the Cockcroft-Gault 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 provides an estimate of glomerular filtration rate.

2. How Does the Calculator Work?

The calculator uses the Cockcroft-Gault equation:

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

Where:

\( Age \) — Age in years
\( Weight \) — Body weight in kilograms
\( SCr \) — Serum creatinine in mg/dL
\( 0.85 \) — Correction factor for female gender
\( 72 \) — Constant factor in the equation

Explanation: The equation estimates creatinine clearance based on the inverse relationship between serum creatinine and renal function, adjusted for age-related decline and gender differences in muscle mass.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance is crucial for medication dosing adjustments, assessing renal function, and identifying patients at risk for drug toxicity due to impaired kidney 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: Why use Cockcroft-Gault equation?
A: It is widely validated for drug dosing adjustments and provides a practical estimate of renal function for clinical decision making.

Q2: What are normal CrCl values?
A: Normal CrCl is approximately 90-120 mL/min for young adults, decreasing with age. Values below 60 mL/min indicate renal impairment.

Q3: When should this calculation be used?
A: Primarily for drug dosing adjustments in patients with known or suspected renal impairment, especially for medications with narrow therapeutic windows.

Q4: Are there limitations to this equation?
A: Less accurate in elderly, obese, malnourished patients, and those with unstable renal function. May overestimate GFR in patients with low muscle mass.

Q5: How does this differ from eGFR?
A: Cockcroft-Gault estimates creatinine clearance, while eGFR estimates glomerular filtration rate. Many drugs still use CrCl for dosing recommendations.