Estimated Creatinine Clearance Calc

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 for assessing kidney function.

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

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 CrCl Calculation

Details: Creatinine clearance estimation is essential for drug dosing adjustments, particularly for medications with narrow therapeutic windows that are renally excreted. It also helps in staging chronic kidney disease.

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 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 may indicate renal impairment.

Q3: When is Cockcroft-Gault preferred over other equations?
A: Cockcroft-Gault is commonly used for drug dosing adjustments, especially in older medications and clinical trials.

Q4: Are there limitations to this equation?
A: Less accurate in extremes of age, obesity, malnutrition, amputees, and patients with rapidly changing kidney function or muscle mass.

Q5: Should ideal body weight be used?
A: For obese patients, some guidelines recommend using ideal body weight rather than actual body weight in the calculation.