Estimated 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:

Estimated CrCl:

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1. What is the Creatinine Clearance Calculator?

The Creatinine Clearance Calculator estimates kidney function using the Cockcroft-Gault equation. It calculates the rate at which creatinine is cleared from the blood by the kidneys, providing an important measure of renal 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 creatinine clearance based on age, weight, serum creatinine level, and gender, with females having approximately 15% lower creatinine production.

3. Importance of CrCl Calculation

Details: Creatinine clearance is crucial for assessing kidney function, determining appropriate drug dosages (especially for renally excreted medications), and monitoring patients with 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 using the Cockcroft-Gault equation, while eGFR estimates glomerular filtration rate using different equations like CKD-EPI or MDRD.

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 impaired kidney function.

Q3: When is CrCl preferred over eGFR?
A: CrCl is often preferred for drug dosing adjustments, particularly for medications with narrow therapeutic windows that are renally excreted.

Q4: What are the limitations of the Cockcroft-Gault equation?
A: It may overestimate CrCl in obese patients, elderly, and those with reduced muscle mass. It's less accurate in patients with unstable renal function.

Q5: Should ideal body weight be used?
A: For obese patients (BMI > 30), some clinicians use ideal body weight in the calculation to avoid overestimation of renal function.