Clincalc 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 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 provides an estimate of glomerular filtration rate.

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:

\( CrCl \) — Creatinine clearance (mL/min)
\( Age \) — Age in years
\( Weight \) — Body weight in kilograms
\( SCr \) — Serum creatinine (mg/dL)
0.85 — Female multiplier

Explanation: The equation estimates creatinine clearance based on demographic and laboratory values, with adjustment for gender differences in muscle mass.

3. Importance of Creatinine Clearance Calculation

Details: Creatinine clearance estimation is essential for drug dosing adjustments, assessing renal function, and monitoring patients with kidney disease or those receiving nephrotoxic medications.

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. CrCl is often preferred for drug dosing.

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

Q3: When should ideal body weight be used?
A: For obese patients (BMI > 30), ideal body weight may be used instead of actual weight to avoid overestimation of renal function.

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

Q5: Why is gender adjustment important?
A: Women typically have lower muscle mass than men, resulting in lower creatinine production and requiring adjustment in the calculation.