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      Calc Function

    • Calcs that help predict probability of a diseaseDiagnosis
    • Subcategory of 'Diagnosis' designed to be very sensitiveRule Out
    • Disease is diagnosed: prognosticate to guide treatmentPrognosis
    • Numerical inputs and outputsFormula
    • Med treatment and moreTreatment
    • Suggested protocolsAlgorithm





    Chief Complaint


    Organ System


    Patent Pending

    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
    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.
    Dr. Andrew S. Levey

    About the Creator

    Andrew S. Levey, MD, is a professor of medicine and Dr. Gerald J. and Dorothy R. Friedman professor emeritus at Tufts University School of Medicine in Massachusetts. He is also chief emeritus of the William B. Schwartz Division of Nephrology at Tufts. For more than 20 years, he has been at the forefront of the development of equations to estimate glomerular filtration rate from serum creatinine, cystatin C and novel filtration markers using large databases, including the widely-used Modification of Diet in Renal Disease (MDRD) Study and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations. Dr. Levey’s research interests include measurement and estimation of kidney function, epidemiology and clinical trials in chronic kidney disease.

    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

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