Estimated glomerular filtration rate (eGFR) without race coefficient

What it is and when to use it

The CKD-EPI 2021 (creatinine) equation estimates the glomerular filtration rate (eGFR) in mL/min/1.73 m² from serum creatinine, age and sex, without race as a variable. It is the recommended tool for estimating kidney function and classifying chronic kidney disease (CKD). The KDIGO 2024 CKD guideline and the U.S. nephrology societies (NKF-ASN Task Force) endorse this race-free equation as the standard for eGFR calculation in clinical practice.

How to interpret it

eGFR is classified into KDIGO G categories: G1 ≥90 (normal or high), G2 60-89 (mildly decreased), G3a 45-59 (mild-to-moderate), G3b 30-44 (moderate-to-severe), G4 15-29 (severe) and G5 <15 (kidney failure). An eGFR <60 sustained for ≥3 months defines CKD, as does the presence of markers of kidney damage (such as albuminuria) with eGFR ≥60. It should be staged together with albuminuria (categories A1-A3) to estimate the full risk of progression and cardiovascular events.

Limitations and when not to use it

Validated in adults; it should not be applied to those under 18 years (the CKiD/Schwartz equation is used instead). The estimate loses reliability in unstable kidney function (acute kidney injury), extremes of muscle mass (amputation, paraplegia, bodybuilding, cachexia, sarcopenia), pregnancy, very high- or low-protein diets, and creatine supplementation. It does not assess albuminuria or tubular damage, so a normal eGFR alone does not exclude CKD; it must always be combined with the urine albumin-to-creatinine ratio.

Frequently asked questions

What is the difference between CKD-EPI 2021 and the 2009 version?

The 2021 version removes the race (Black) coefficient that the 2009 version included, so it gives the same result regardless of ethnic background; it may slightly lower the estimated eGFR in people previously classified as Black.

Do I need a 24-hour urine collection for this calculation?

No. The equation requires only serum creatinine, age and sex; no urine collection or body weight is needed.

When should the cystatin C variant be used instead of creatinine alone?

KDIGO recommends confirming with the CKD-EPI 2021 creatinine-cystatin C equation when the creatinine-based eGFR is uncertain or when a more accurate estimate is needed for important clinical decisions, such as drug dosing or donor evaluation.