CKD-EPI Creatinine Equation (2021)

Expressed as a single equation:

eGFRcr = 142 x min(Scr/κ, 1)α x max(Scr/κ, 1)-1.200 x 0.9938Age x 1.012 [if female]


Scr = standardized serum creatinine in mg/dL
κ = 0.7 (females) or 0.9 (males)
α = -0.241 (female) or -0.302 (male)
min(Scr/κ, 1) is the minimum of Scr/κ or 1.0
max(Scr/κ, 1) is the maximum of Scr/κ or 1.0
Age (years)


Creatinine is assayed using methods that are traceable to IDMS assigned NIST certified reference materials. To learn more, go to

Clinical Use

  • Recommended method for estimating GFR in adults.
  • Designed for use with laboratory creatinine values that are standardized to IDMS.
  • Estimates GFR from serum creatinine, age, sex, and race.
  • More accurate than the MDRD Study equation, particularly in people with higher levels of GFR.
  • Based on the same four variables as the MDRD Study equation, but uses a 2-slope “spline” to model the relationship between estimated GFR and serum creatinine, and a different relationship for age, sex and race.
  • 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 CKD-EPI equation to report estimated GFR in adults.
  • Developed in 2009 by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI).


  1. Inker LA, Eneanya ND, Coresh J, et al. New creatinine- and cystatin C–based equations to estimate GFR without race. N Engl J Med. 2021;385:1737-1749.
  2. Delgado C, Baweja M, Crews DC, 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. Am J Kidney Dis. 2021;78(1):103-115.
  3. Kramer HJ, Jaar BG, Choi MJ, et al,; National Kidney Foundation Kidney Disease Outcomes Quality Initiative. An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative. Am J Kidney Dis. 2022;80(6):691-696.