National Kidney Foundation eGFR Calculation

NKF Recommended CKD-EPI 2021 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 Recommended eGFR Calculation?

The National Kidney Foundation (NKF) recommended CKD-EPI 2021 equation estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex. This updated equation provides improved accuracy for assessing kidney function across diverse populations.

2. How Does The Calculator Work?

The calculator uses the NKF recommended CKD-EPI 2021 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: This updated equation incorporates refined coefficients based on contemporary population data for more accurate GFR estimation.

3. Importance Of eGFR Calculation

Details: Accurate GFR estimation is essential for early detection of chronic kidney disease, appropriate staging, and guiding clinical decisions regarding medication dosing and referral to nephrology.

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).

5. Frequently Asked Questions (FAQ)

Q1: What Are The Key Updates In The NKF 2021 Equation?
A: The 2021 update features revised coefficients (142, -1.200, 0.9938) and gender-specific parameters based on contemporary population data for improved accuracy.

Q2: How Does This Compare To Previous CKD-EPI Equations?
A: This version provides better performance across diverse populations and improved calibration with measured GFR values.

Q3: What Are Normal eGFR Values With This Equation?
A: Normal eGFR is generally ≥90 mL/min/1.73m². Values below 60 mL/min/1.73m² persisting for 3+ months indicate chronic kidney disease.

Q4: Are There Population Limitations For This Equation?
A: As with all estimating equations, caution is advised in extremes of age, body composition, pregnancy, and rapidly changing kidney function.

Q5: Is Race Still A Factor In This Equation?
A: The NKF 2021 equation removes race as a variable, focusing on creatinine, age, and sex for more equitable GFR estimation.