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 Creatinine Clearance Calculator?

The Creatinine Clearance Calculator estimates kidney function using the Cockcroft-Gault formula, which calculates the rate at which creatinine is cleared from the blood by the kidneys. This measurement helps assess renal function and guide medication dosing.

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 — Gender correction factor for females

Explanation: The formula estimates creatinine clearance based on age, weight, serum creatinine level, and gender, providing an approximation of glomerular filtration rate.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance is crucial for assessing kidney function, diagnosing renal impairment, adjusting drug dosages for renally excreted medications, and monitoring patients with 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 between 1-120, weight > 0, creatinine > 0).

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 used for drug dosing.

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

Q3: Why is there a gender factor in the formula?
A: Women typically have less muscle mass than men, resulting in lower creatinine production. The 0.85 factor adjusts for this physiological difference.

Q4: Are there limitations to the Cockcroft-Gault formula?
A: Yes, it may overestimate CrCl in obese patients, elderly, those with extreme muscle mass, and patients with unstable renal function.

Q5: 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 overestimation of renal function.