CKD-EPI Creatinine Equation (2021)

Expressed as a single equation:

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

where:

Assays

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

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).

References

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.