About the CKD-EPI 2021 eGFR Equation
The Estimated Glomerular Filtration Rate (eGFR) is the primary clinical indicator used by nephrologists to assess renal (kidney) function. It measures how well your kidneys are filtering creatinine (a waste product from muscle breakdown) out of your blood.
The National Kidney Foundation and the American Society of Nephrology formally recommend using the updated 2021 CKD-EPI equation.
The Shift to a Race-Free Clinical Standard
Importantly, the 2021 CKD-EPI equation is race-free. Previous versions of the eGFR calculation included a race multiplier for Black patients based on outdated clinical assumptions about muscle mass. This multiplier was removed to promote health equity, as it systematically overestimated kidney function in Black patients, causing harmful delays in the diagnosis and treatment of chronic kidney disease.
Understanding the Stages of CKD
Nephrologists classify chronic kidney disease into five distinct stages based on the eGFR output:
| Stage | eGFR Range | Clinical Description |
|---|---|---|
| Stage 1 (G1) | ≥ 90 | Normal or high kidney function |
| Stage 2 (G2) | 60 - 89 | Mildly decreased kidney function |
| Stage 3a (G3a) | 45 - 59 | Mild to moderately decreased kidney function |
| Stage 3b (G3b) | 30 - 44 | Moderate to severely decreased kidney function |
| Stage 4 (G4) | 15 - 29 | Severely decreased kidney function |
| Stage 5 (G5) | < 15 | Kidney failure (ESRD) |