Kidney UK GFR Calculator

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 Kidney UK GFR Calculator?

The Kidney UK GFR Calculator uses the CKD-EPI 2021 equation to estimate glomerular filtration rate (GFR) from serum creatinine, age, and sex. This updated equation provides improved accuracy in assessing kidney function compared to previous versions.

2. How Does the Calculator Work?

The calculator uses the 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 recent population studies, providing more accurate GFR estimation across different demographic groups.

3. Importance of eGFR Calculation

Details: Accurate GFR estimation is essential for early detection of chronic kidney disease, monitoring disease progression, and guiding appropriate clinical management and treatment decisions.

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) for accurate results.

5. Frequently Asked Questions (FAQ)

Q1: What's new in the CKD-EPI 2021 equation?
A: The 2021 version features updated coefficients (142, -1.200, 0.9938) and refined gender multipliers based on larger, more diverse population datasets.

Q2: How does this differ from the original CKD-EPI?
A: The 2021 equation uses 142 instead of 141, -1.200 instead of -1.209, 0.9938 instead of 0.993, and different alpha values for improved accuracy.

Q3: What are the clinical implications of using this equation?
A: This updated equation may reclassify some patients' CKD stages and could affect medication dosing decisions based on renal function.

Q4: Is race no longer included in this equation?
A: Yes, the CKD-EPI 2021 equation removes race as a variable, focusing on creatinine, age, and sex only for more equitable GFR estimation.

Q5: When should this equation be used clinically?
A: This equation is recommended for adults with stable kidney function and should be validated against local laboratory standards before full implementation.