CKD EPI GFR Calculator NKF

NKF 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 NKF CKD-EPI GFR Equation?

The NKF CKD-EPI (National Kidney Foundation Chronic Kidney Disease Epidemiology Collaboration) equation estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex. This version provides enhanced accuracy for kidney function assessment with updated coefficients.

2. How Does the Calculator Work?

The calculator uses the NKF 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 accounts for non-linear relationship between creatinine and GFR, with optimized coefficients for different demographic groups.

3. Importance of eGFR Calculation

Details: Accurate GFR estimation is essential for diagnosing chronic kidney disease, staging disease severity, and guiding appropriate medication dosing and treatment decisions.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. All values must be valid (creatinine > 0, age between 1-120 years).

5. Frequently Asked Questions (FAQ)

Q1: What makes the NKF CKD-EPI equation different?
A: This version uses updated coefficients (142, -1.200, 0.9938) for improved accuracy across various populations.

Q2: What are normal eGFR values?
A: Normal GFR is generally ≥90 mL/min/1.73m², though values naturally decline with age. Persistent values below 60 indicate chronic kidney disease.

Q3: When is the best time to measure creatinine?
A: Morning fasting samples are preferred, but random samples are acceptable. Avoid testing after high-protein meals or intense physical activity.

Q4: Are there limitations to this equation?
A: Less accurate in extreme age groups, amputees, pregnant women, individuals with unstable muscle mass, or those with rapidly changing kidney function.

Q5: Can this equation be used for medication dosing?
A: While useful for screening, for precise drug dosing in critical situations, measured GFR methods may be necessary.