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Cockcroft-Gault Equation:
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The Cockcroft-Gault formula is a widely used method for estimating creatinine clearance (CrCl), which serves as a surrogate for glomerular filtration rate (GFR). It estimates renal function based on age, weight, and serum creatinine levels.
The calculator uses the Cockcroft-Gault equation:
Where:
Explanation: The formula accounts for the natural decline in renal function with age and differences in muscle mass between genders, providing an estimate of creatinine clearance rate.
Details: Creatinine clearance estimation is essential for assessing kidney function, guiding drug dosing (especially for renally excreted medications), and monitoring patients with renal impairment.
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).
Q1: What is the difference between CrCl and eGFR?
A: CrCl estimates creatinine clearance while eGFR estimates glomerular filtration rate. Both assess kidney function but use different equations and may yield different results.
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: Why is weight included in the formula?
A: Weight is included as creatinine production correlates with muscle mass, which is proportional to body weight.
Q4: Are there limitations to this formula?
A: Less accurate in extremes of age, obesity, malnutrition, amputees, and patients with rapidly changing renal function or unstable creatinine levels.
Q5: When is Cockcroft-Gault preferred over other equations?
A: Often preferred for drug dosing adjustments, particularly for medications with narrow therapeutic windows that are renally excreted.