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Cockcroft-Gault Formula:
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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, particularly for drugs that are renally eliminated.
The calculator uses the Cockcroft-Gault formula:
Where:
Explanation: The formula estimates the rate at which creatinine is cleared from the blood by the kidneys, providing an approximation of glomerular filtration rate.
Details: Creatinine clearance is essential for assessing kidney function, diagnosing renal impairment, and adjusting medication dosages for drugs that are primarily excreted by the kidneys.
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).
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 or MDRD. They serve similar purposes but use different calculations.
Q2: What are normal CrCl values?
A: Normal CrCl is approximately 95-125 mL/min for young adults, decreasing with age. Values below 60 mL/min may indicate renal impairment.
Q3: When should CrCl be used for drug dosing?
A: CrCl is commonly used for dosing medications like antibiotics, antivirals, and chemotherapeutic agents that require renal adjustment.
Q4: Are there limitations to the Cockcroft-Gault formula?
A: Yes, it may overestimate CrCl in obese patients, elderly, and those with unstable creatinine levels. It's less accurate at extremes of age and body composition.
Q5: Should ideal body weight be used?
A: For obese patients, some guidelines recommend using ideal body weight rather than actual body weight in the calculation to avoid overestimation.