eGFR Calculator (CKD-EPI Formula)

CKD-EPI Equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{age} \times (1.012 \text{ if female}) \]

Estimated GFR (eGFR):

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1. What Is The eGFR Calculator (CKD-EPI Formula)?

The eGFR Calculator using the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) formula estimates glomerular filtration rate from serum creatinine, age, and sex. This equation provides accurate assessment of kidney function and is widely used in clinical practice.

2. How Does The Calculator Work?

The calculator uses the CKD-EPI equation:

\[ eGFR = 142 \times \min(Scr/\kappa, 1)^\alpha \times \max(Scr/\kappa, 1)^{-1.200} \times 0.9938^{age} \times (1.012 \text{ if female}) \]

Where:

\( Scr \) — Serum creatinine (mg/dL)
\( \kappa \) — 0.7 (female) or 0.9 (male)
\( \alpha \) — -0.241 (female) or -0.302 (male)
\( age \) — Age in years
1.012 — Female multiplier

Explanation: The equation models the non-linear relationship between serum creatinine and glomerular filtration rate, with optimized coefficients for different demographic characteristics.

3. Importance Of eGFR Calculation

Details: Accurate estimation of glomerular filtration rate is essential for detecting kidney dysfunction, staging chronic kidney disease, monitoring disease progression, and adjusting medication dosages based on renal function.

4. Using The Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. Ensure all values are valid (creatinine > 0, age between 1-120 years). The calculator will provide the estimated GFR in mL/min/1.73m².

5. Frequently Asked Questions (FAQ)

Q1: What Are The Advantages Of This CKD-EPI Formula?
A: This version of the CKD-EPI equation provides improved accuracy across the full spectrum of kidney function and better performance in populations with normal or mildly reduced GFR.

Q2: What Is Considered A Normal eGFR Value?
A: Normal eGFR is generally ≥90 mL/min/1.73m². Values between 60-89 may indicate mild kidney dysfunction, while values below 60 for three months or more suggest chronic kidney disease.

Q3: When Is The Best Time To Measure Serum Creatinine?
A: Morning fasting samples are preferred, but random samples are acceptable. Avoid testing shortly after high-protein meals or intense physical activity.

Q4: What Are The Limitations Of This Equation?
A: The equation may be less accurate in extreme age groups, pregnant women, individuals with unusual muscle mass, amputees, and those with rapidly changing kidney function.

Q5: Can This Calculator Be Used For Medication Dosing?
A: While useful for screening and monitoring, for precise drug dosing in critical situations, measured GFR methods may be necessary for certain patient populations.