Most Accurate GFR Calculator

CKD-EPI 2021 Equation (without race):

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

Estimated GFR:

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1. What is the CKD-EPI 2021 Equation?

The CKD-EPI 2021 equation estimates glomerular filtration rate (GFR) from serum creatinine, age, and sex without using race as a variable. This updated version provides a more equitable assessment of kidney function across all populations.

2. How Does the Calculator Work?

The calculator uses the CKD-EPI 2021 equation (without race):

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

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 equation represents the most current and accurate method for estimating GFR without racial bias, using updated coefficients from large population studies.

3. Importance of GFR Calculation

Details: GFR estimation is essential for detecting kidney disease, monitoring progression, and guiding treatment decisions. The 2021 equation improves equity in kidney disease diagnosis and management.

4. Using the Calculator

Tips: Enter serum creatinine in mg/dL, age in years, and select gender. For most accurate results, creatinine should be measured using standardized methods.

5. Frequently Asked Questions (FAQ)

Q1: Why was race removed from the equation?
A: Race is a social construct, not a biological one. The 2021 equation provides equally accurate estimates without using race, promoting health equity.

Q2: How does this compare to the older CKD-EPI equation?
A: The 2021 equation maintains accuracy while eliminating race adjustment, with slightly different coefficients based on newer data.

Q3: What are normal GFR values?
A: Normal is generally ≥90 mL/min/1.73m². Values decline with age, but below 60 for 3+ months indicates chronic kidney disease.

Q4: Are there limitations to this equation?
A: As with all creatinine-based equations, accuracy may be reduced in extremes of body composition, amputees, and those with rapidly changing kidney function.

Q5: Should this be used for children?
A: No, this equation is validated for adults only. Pediatric GFR estimation requires different equations.