CKD-EPI Creatinine Equation (2021)


Expressed as a single equation:

eGFR =
min(standardized Scr/K, 1)α *
max(standardized Scr/K, 1)-1.200 *
0.9938Age *
1.012 [if female]

Abbreviations / Units

eGFR (estimated glomerular filtration rate) = mL/min/ 1.73 m2

Scr (serum creatinine) = mg/dL

K = 0.7 (females) or 0.9 (males)

α = -0.241 (females) or -0.302 (males)

min = indicates the minimum of Scr/K or 1

max = indicates the maximum of Scr/K or 1

Clinical Use

  • The Recommended method for estimating GFR in adults from the National Kidney Foundation is the 2021 CKD-EPI equations.
  • Designed for use with laboratory creatinine values that are standardized to IDMS. (See "About GFR" button.)
  • Estimates GFR from serum creatinine, age and sex
  • More accurate than the MDRD Study equation, particularly in people with higher levels of GFR.
  • The CKD-EPI equation are modeled using least squares linear regression to relate log transformed measured GFR to log-transformed filtration markers, age and sex with two slope splines for creatinine
  • Some clinical laboratories are still reporting GFR estimates using the MDRD Study equation. The National Kidney Foundation has recommended that clinical laboratories should begin using the 2021 CKD-EPI equation to report estimated GFR using creatinine and cystatin C.


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  2. Levey AS, Stevens LA. Estimating GFR using the CKD Epidemiology Collaboration (CKD-EPI) creatinine equation: more accurate GFR estimates, lower CKD prevalence estimates, and better risk predictions. Am J Kidney Dis. Apr 2010; 55(4): 622-627.
  3. Matsushita K, Selvin E, Bash LD, Astor BC, Coresh J. Risk implications of the new CKD Epidemiology Collaboration (CKD-EPI) equation compared with the MORD Study equation for estimated GFR: the Atherosclerosis Risk in Communities (ARIC) Study. Am J Kidney Dis. Apr 201O; 55(4): 648-659.
  4. White SL, Polkinghorne KR, Atkins RC, Chadban SJ. Comparison of the prevalence and mortality risk of CKD in Australia using the CKD Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MORD) Study GFR estimating equations: the AusDiab (Australian Diabetes, Obesity and Lifestyle) Study. Am J Kidney Dis. Apr 2010; 55(4): 660-670.
  5. Becker BN, Vassalotti JA. A software upgrade: CKD testing in 2010. Am J Kidney Dis. Jan 2009; 55(1): 8-10.
  6. Frequently Asked Questions About GFR Estimates. New York: The National Kidney Foundation; 2011.
  7. National Kidney Foundation. KDOQI clinical practice guidelines for chronic kidney disease: evaluation, classification, and stratification. Am J Kidney Dis. Feb 2002; 39 (Suppl 1): S1-266.