Glomerular filtration rate (GFR) is the best overall index of kidney function and is used to stage chronic kidney disease (CKD), guide drug dosing, and time renal replacement therapy. The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation was developed in 2009 and updated in 2021 to remove the race coefficient, making it race-free and reducing racial disparities in CKD care. It uses serum creatinine, age, and sex to estimate GFR and is more accurate than the Cockcroft-Gault and MDRD equations, particularly at higher GFR values. The National Kidney Foundation now recommends the 2021 race-free CKD-EPI as the primary equation for CKD staging.
Glomerular filtration rate (GFR) is the best overall index of kidney function and is used to stage chronic kidney disease (CKD), guide drug dosing, and time renal replacement therapy. The CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) creatinine equation was developed in 2009 and updated in 2021 to remove the race coefficient, making it race-free and reducing racial disparities in CKD care. It uses serum creatinine, age, and sex to estimate GFR and is more accurate than the Cockcroft-Gault and MDRD equations, particularly at higher GFR values. The National Kidney Foundation now recommends the 2021 race-free CKD-EPI as the primary equation for CKD staging.
Validated In
Pooled data from 30+ studies including >8,000 patients with measured GFR
CKD-EPI Collaboration (Andrew S. Levey, Lesley A. Inker, et al.)
CKD-EPI Creatinine (2021)
Kappa: 0.7 (F), 0.9 (M) | Alpha: -0.241 (F), -0.302 (M) | Race-free
GFR ≥90 mL/min/1.73m² = G1
Normal or high. Not CKD unless other markers of kidney damage present.
GFR 60-89 = G2
Mildly decreased. Not CKD unless other markers present.
GFR 45-59 = G3a
Mild-to-moderately decreased. Nephrology referral consideration.
GFR 30-44 = G3b
Moderately to severely decreased. Nephrology referral recommended.
GFR 15-29 = G4
Severely decreased. Prepare for renal replacement therapy.
GFR <15 = G5
Kidney failure. Dialysis or transplant required.
Albuminuria (ACR)
A1 (<30 mg/g), A2 (30-300), A3 (>300) — combined with GFR for CKD risk stratification
CKD is diagnosed when GFR <60 OR markers of kidney damage (albuminuria, haematuria) are present for >3 months — a single low GFR is not sufficient.
When cystatin C is also measured, the combined CKD-EPI Cr-Cys equation provides the most accurate eGFR estimate, especially in patients with unusual body habitus or muscle mass.
The Cockcroft-Gault equation is preferred for drug dosing (not CKD staging) because most pharmacokinetic studies were done using C-G.
eGFR can be misleadingly high in patients with significantly reduced muscle mass (cachexia, amputees, elderly) — use cystatin C-based equation in these cases.
SGLT2 inhibitors (dapagliflozin, empagliflozin) reduce CKD progression by ~40% and are now first-line therapy for CKD with albuminuria regardless of diabetes status (DAPA-CKD, EMPA-KIDNEY trials).
For Ramadan fasting patients or those with acute changes in creatinine, interpret eGFR trends rather than single values.
Inker LA, et al. New Creatinine- and Cystatin C-Based Equations to Estimate GFR without Race. N Engl J Med. 2021;385(19):1737-1749.
Levey AS, et al. A New Equation to Estimate Glomerular Filtration Rate. Ann Intern Med. 2009;150(9):604-612.
KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024;105(4S):S117-S314.