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    CKD-EPI Equations for Glomerular Filtration Rate (GFR)

    Estimates GFR based on serum creatinine, serum cystatin C, or both.


    The 2021 CKD-EPI equation is now the recommended standard. This version does not include race, as do the 2009 and 2012 CKD-EPI creatinine and creatinine-cystatin C equations. See here for more on our approach to addressing race and bias on MDCalc.

    With the 2021 equation, for the same creatinine value, the 2021 equation will estimate a lower GFR for Black patients and a higher GFR for non-Black patients.


    For use in patients with stable kidney function. While the combined creatinine and cystatin C equation can add accuracy, cystatin c is not available in all laboratories and the creatinine-based equation is adequate for many clinical purposes.

    2021 CKD-EPI creatinine is currently recommended by the ASN and NKF for GFR reporting in the United States.

    When to Use
    Why Use
    • Patients with chronic kidney disease (not acute), to measure kidney function.
    • CKD-EPI Creatinine is more commonly available.
    • 2021 CKD-EPI creatinine-cystatin is recommended as a confirmatory test in patients at extremes of body type (e.g. obese patients, high or low muscle mass).
    • In 2021 new equations were created to remove the race components from the prior CKD-Epi equations and should be the new standard equations; we continue to offer the prior equations for comparison/trending.
    • Creatinine-based estimates of kidney function by glomerular filtration rate (GFR) are less accurate in certain populations including patients with diabetes (before progression to overt nephropathy with diminished GFR), pregnant women, those with unusual body mass (e.g. obese, severely malnourished, amputees, paraplegics, etc).
    • Not for use in patients on dialysis.

    The CKD-EPI equation performs superiorly to the MDRD Equation in patients with normal or mildly reduced estimated GFR (eGFR), and just as well in patients with an eGFR of <60 mL/min/m2. It is used most widely by nephrologists and understood to be the most accurate means of non-invasively assessing GFR in the United States.

    2021 CKD-EPI Creatinine
    2021 CKD-EPI Creatinine-Cystatin C
    2009 CKD-EPI Creatinine
    2012 CKD-EPI Cystatin C
    2012 CKD-EPI Creatinine–Cystatin C


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    Creator Insights
    Dr. Andrew S. Levey

    About the Creator

    Andrew S. Levey, MD, is the chief of the nephrology division at Tufts Medical Center and the Dr. Gerald J. and Dorothy R. Friedman Professor at Tufts University School of Medicine. His clinical interests include chronic kidney disease (CKD), diabetic kidney disease, and systemic lupus erythematosus. Dr. Levey’s research focuses on laboratory measures to estimate kidney function, new therapies, and the development of clinical practice guidelines for CKD.

    To view Dr. Andrew S. Levey's publications, visit PubMed

    Dr. Lesley A. Inker

    About the Creator

    Lesley A. Inker, MD, MS, is an associate professor at Tufts University School of Medicine, an attending physician in the William B. Schwartz, MD Division of Nephrology at Tufts Medical Center, and medical director of the Kidney And Blood Pressure Center at Tufts Medical Center in Massachusetts. Dr. Inker's primary research interests are in GFR measurement and estimation, alternative endpoints for clinical trials of kidney disease progression, and epidemiology and outcomes related to CKD.

    To view Dr. Lesley A. Inker's publications, visit PubMed

    The CKD Epidemiology Collaboration (CKD-EPI)

    About the Creator

    The CKD Epidemiology Collaboration (CKD-EPI) is a research group  with interests in measurement  and estimation of GFR (CKD-EPI GFR) and evaluation of surrogate endpoints for clinical trials in CKD (CKD-EPI CT). CKD-EPI was founded by Dr. Andrew S. Levey who served as Director from  2004 to 2018 and continues to serve as co-director. Dr. Lesley A. Inker has been the Director of the Data Coordinating Center (DCC) from 2004 and Co-Director since 2018.

    Content Contributors
    • Omar Aziz, MD
    About the Creator
    Dr. Andrew S. Levey
    Dr. Lesley A. Inker
    The CKD Epidemiology Collaboration (CKD-EPI)
    Content Contributors
    • Omar Aziz, MD