eGFR Calculator NIH

NIH 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 NIH CKD-EPI 2021 Equation?

The NIH CKD-EPI 2021 equation is an updated version of the CKD-EPI equation that estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex. This newer version provides enhanced accuracy in GFR estimation across diverse populations.

2. How Does the Calculator Work?

The calculator uses the NIH 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 more recent population data, improving accuracy particularly in borderline kidney function cases.

3. Importance of eGFR Calculation

Details: Accurate GFR estimation is essential for early detection of kidney disease, monitoring disease progression, and making informed clinical decisions regarding medication adjustments and treatment planning.

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). Use recent laboratory results for optimal accuracy.

5. Frequently Asked Questions (FAQ)

Q1: What's new in the NIH CKD-EPI 2021 equation?
A: The 2021 version features updated coefficients (142, -1.200, 0.9938) and gender-specific parameters based on more contemporary population data.

Q2: How does this differ from the original CKD-EPI equation?
A: The NIH 2021 version uses different numerical coefficients and exponents, providing improved accuracy across the full spectrum of kidney function.

Q3: Is race no longer included in this equation?
A: Yes, the NIH 2021 equation removes race as a variable, focusing on creatinine, age, and sex only for more equitable GFR estimation.

Q4: What are the clinical applications of this calculator?
A: Useful for screening, diagnosing CKD stages, monitoring kidney function over time, and guiding medication dosing in clinical practice.

Q5: Are there limitations to this equation?
A: As with all estimation equations, limitations exist in extremes of age, body composition, and certain medical conditions where measured GFR may be preferred.