eGFR Cockroft Formula Calculator

Cockcroft-Gault Formula:

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

Age (years):

years

Weight (kg):

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 serves as a surrogate for glomerular filtration rate (GFR). It was developed in 1976 and remains 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:

\( Age \) — Age in years
\( Weight \) — Body weight in kilograms
\( Scr \) — Serum creatinine in mg/dL
0.85 — Correction factor for female gender

Explanation: The formula estimates creatinine clearance based on age, weight, serum creatinine, and gender, providing an approximation of kidney function for medication dosing purposes.

3. Importance of CrCl Calculation

Details: Creatinine clearance estimation is essential for appropriate dosing of medications that are eliminated by the kidneys, preventing 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 1-120 years, weight > 0 kg, creatinine > 0 mg/dL).

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between CrCl and eGFR?
A: CrCl estimates creatinine clearance using the Cockcroft-Gault formula, while eGFR typically refers to estimates using MDRD or CKD-EPI equations. CrCl is often preferred for drug dosing.

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 is ideal body weight used instead of actual weight?
A: For obese patients (BMI > 30), some guidelines recommend using ideal body weight to avoid overestimating renal function.

Q4: What are the limitations of the Cockcroft-Gault formula?
A: It may overestimate CrCl in elderly patients, those with low muscle mass, and in hospitalized or critically ill patients.

Q5: Is this formula validated for all populations?
A: The formula was developed primarily in Caucasian populations and may require adjustment for other ethnic groups or specific clinical situations.