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CKD-EPI GFR Calculator

by Creative Labs Medical Calculators

Calculate glomerular filtration rate using the 2021 CKD-EPI creatinine equation. Recommended by ASN and NKF for accurate kidney function assessment.

GFR Calculator

Enter patient information to calculate estimated glomerular filtration rate (eGFR) using the 2021 CKD-EPI equation.

The 2021 equation does not include race. This option is provided for comparison with older equations.

How to Use This Tool

1. Select patient sex (male or female)

2. Enter age in years (18-120)

3. Enter serum creatinine value and select units

4. Black race is optional for comparison purposes only

5. Click "Calculate GFR" for results

GFR Results

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Enter values to calculate

Kidney Function Chart


CKD Stages

Medical Guidance

Complete the calculator to receive personalized medical advice based on your GFR result.

About the 2021 CKD-EPI Equation

The 2021 CKD-EPI creatinine equation is now the recommended standard for estimating glomerular filtration rate (GFR). This version eliminates race as a variable, addressing health equity concerns in kidney disease diagnosis and management.

Key Features

Important Note

The 2021 equation estimates a lower GFR for Black patients and a higher GFR for non-Black patients compared to previous equations using the same creatinine value. This calculator is for clinical decision support only and should not replace professional medical advice.

Frequently Asked Questions

What is the CKD-EPI equation? +

The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation is a formula used to estimate glomerular filtration rate (GFR) from serum creatinine levels. The 2021 version is the current standard and does not include race as a variable.

Why was race removed from the 2021 equation? +

Race was removed to address health equity concerns and because it is a social construct rather than a biological variable. The 2021 equation provides more equitable GFR estimates across all racial groups.

When should I use cystatin C testing? +

Cystatin C testing can add accuracy when creatinine-based estimates are unreliable (e.g., in patients with extreme muscle mass, amputations, or specific diets). However, creatinine-based equations are adequate for most clinical purposes.

What do the different CKD stages mean? +

CKD is classified into 5 stages based on GFR: Stage 1 (≥90 mL/min) - kidney damage with normal function; Stage 2 (60-89) - mild reduction; Stage 3 (30-59) - moderate reduction; Stage 4 (15-29) - severe reduction; Stage 5 (<15) - kidney failure.

Is this calculator suitable for all patients? +

This calculator is designed for adults (18+) with stable kidney function. It may not be accurate for pregnant women, hospitalized patients, or those with rapidly changing kidney function. Always consult a healthcare provider for medical decisions.

References & Sources

Scientific References

This calculator is based on peer-reviewed scientific literature and clinical guidelines:

  • 2021 CKD-EPI Equation: Inker LA, et al. "New Creatinine- and Cystatin C–Based Equations to Estimate GFR without Race." New England Journal of Medicine. 2021;385(19):1737-1749.
  • NKF-ASN Task Force: Delgado C, et al. "A Unifying Approach for GFR Estimation: Recommendations of the NKF-ASN Task Force on Reassessing the Inclusion of Race in Diagnosing Kidney Disease." American Journal of Kidney Diseases. 2022;79(2):268-288.
  • Original CKD-EPI Study: Levey AS, et al. "A New Equation to Estimate Glomerular Filtration Rate." Annals of Internal Medicine. 2009;150(9):604-612.
  • KDIGO Guidelines: Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. "KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease." Kidney International. 2024;105(4S):S1-S155.
  • Validation Studies: Pottel H, et al. "Estimating Glomerular Filtration Rate for the Full Age Spectrum from Serum Creatinine and Cystatin C." Nephrology Dialysis Transplantation. 2017;32(3):497-507.

Clinical Guidelines

  • National Kidney Foundation. "KDOQI Clinical Practice Guideline for Diabetes and CKD: 2022 Update." American Journal of Kidney Diseases. 2022;79(4S1):S1-S115.
  • American Society of Nephrology. "Position Statement on Race and eGFR." 2021.
  • U.S. Department of Veterans Affairs. "Clinical Practice Guideline for the Management of Chronic Kidney Disease." 2023.

Calculation Methodology

Equation Used: 2021 CKD-EPI creatinine equation (race-free)

Variables: Sex, age, serum creatinine

Units: GFR expressed in mL/min/1.73m²

Limitations: This equation estimates GFR in adults with stable kidney function. It may be less accurate in:

  • Extremes of age (<18 or >80 years)
  • Extremes of body size or muscle mass
  • Pregnancy
  • Hospitalized patients or those with acute kidney injury
  • Certain ethnic groups not well-represented in validation studies

Last Updated: Based on literature current through December 2024

Citation Suggestion

Creative Labs Medical Calculators. CKD-EPI GFR Calculator. Retrieved from https://tools4u.click/ckd-epi-gfr-calculator/

When using this calculator for research or clinical purposes, please also cite the original 2021 CKD-EPI publication.