How To Calculate Creatinine Clearance Canada

Cockcroft-Gault Formula (Canada Adjusted):

\[ CrCl = \frac{(140 - age) \times weight \times 0.85 \text{ (if female)}}{72 \times Scr} \]

Age:

years

Weight:

Serum Creatinine (Scr):

mg/dL

Gender:

Creatinine Clearance (CrCl):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Creatinine Clearance?

Creatinine clearance (CrCl) is a measure of kidney function that estimates the rate at which creatinine is cleared from the blood by the kidneys. The Cockcroft-Gault formula is widely used in Canada for drug dosing adjustments and renal function assessment.

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
\( 0.85 \) — Female adjustment factor
\( 72 \) — Constant for unit conversion

Explanation: This formula estimates creatinine clearance based on age, weight, serum creatinine level, and gender, with specific adjustments for the Canadian healthcare context.

3. Importance of CrCl Calculation in Canada

Details: In Canada, creatinine clearance calculation is essential for appropriate drug dosing, particularly for medications with renal excretion. It helps prevent drug toxicity in patients with impaired kidney function and is used in various clinical guidelines.

4. Using the Calculator

Tips: Enter age in years, weight in kilograms, serum creatinine in mg/dL, and select gender. Ensure all values are valid (age 1-120 years, weight > 0 kg, Scr > 0 mg/dL).

5. Frequently Asked Questions (FAQ)

Q1: Why is the Cockcroft-Gault formula used in Canada?
A: It remains widely accepted in Canadian clinical practice for drug dosing adjustments and is referenced in many Canadian therapeutic guidelines.

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 may indicate renal impairment.

Q3: When should serum creatinine be measured?
A: Ideally, morning fasting samples are preferred. Avoid testing after high-protein meals or strenuous exercise for accurate results.

Q4: Are there limitations to this formula?
A: The formula may overestimate CrCl in obese patients, elderly, and those with extreme muscle mass. It's less accurate in patients with rapidly changing renal function.

Q5: How is CrCl used in drug dosing?
A: Many medications require dose adjustments based on CrCl to prevent accumulation and toxicity, particularly antibiotics, antivirals, and chemotherapeutic agents.