Est Creatinine Clearance Calculator

Cockcroft-Gault Formula:

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

Age:

years

Weight:

Serum Creatinine (SCr):

mg/dL

Gender:

Creatinine Clearance (CrCl):

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1. What is the Cockcroft-Gault Formula?

The Cockcroft-Gault formula 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 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 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 renal excretion. It helps prevent toxicity in patients with impaired kidney function and guides appropriate dosing regimens.

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 estimates glomerular filtration rate using equations like CKD-EPI. CrCl is often preferred for drug dosing.

Q2: What are normal CrCl values?
A: Normal CrCl is approximately 95-125 mL/min for men and 85-115 mL/min for women. Values decrease with age.

Q3: When should ideal body weight be used instead of actual weight?
A: For obese patients (BMI > 30), ideal body weight is often recommended to avoid overestimating CrCl.

Q4: Are there limitations to the Cockcroft-Gault formula?
A: Yes, it may be less accurate in elderly patients, those with extreme body weights, muscle wasting, or rapidly changing renal function.

Q5: Can this calculator be used for pediatric patients?
A: No, the Cockcroft-Gault formula is validated for adults only. Different equations are used for pediatric patients.