Estimate 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:

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) from serum creatinine, age, weight, and gender. It helps assess kidney function and guide medication dosing in clinical practice.

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
\( 0.85 \) — Adjustment factor for female gender

Explanation: The formula estimates creatinine clearance based on the principle that creatinine production is proportional to muscle mass, which decreases with age and differs between genders.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance is crucial for assessing renal function, determining appropriate drug dosages (especially for renally excreted medications), and monitoring kidney disease progression.

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 Cockcroft-Gault, while eGFR estimates glomerular filtration rate using equations like CKD-EPI. They serve similar purposes but use different calculation methods.

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 below these ranges may indicate impaired kidney function.

Q3: When is Cockcroft-Gault formula preferred?
A: It's commonly used for drug dosing adjustments, particularly for medications with narrow therapeutic windows that are renally excreted.

Q4: Are there limitations to this formula?
A: Less accurate in elderly, obese, or severely malnourished patients, and in those with rapidly changing kidney function or extreme muscle mass.

Q5: Should ideal body weight be used?
A: For obese patients, some guidelines recommend using ideal body weight rather than actual weight for more accurate estimation.