What eGFR is
The glomerular filtration rate shows how much blood the kidneys clean per minute. It is the main indicator of kidney function. Measuring it directly is difficult, so GFR is estimated from the level of creatinine in the blood — a product of muscle metabolism that the kidneys excrete.
The CKD-EPI 2021 formula
The 2021 version does not use a race adjustment and is recommended by KDIGO. The result is expressed in mL/min/1.73 m² — per standard body surface area.
KDIGO stages
| Stage | eGFR | Description |
|---|---|---|
| G1 | 90 and above | Normal or high |
| G2 | 60–89 | Mildly decreased |
| G3a | 45–59 | Mildly to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | below 15 | Kidney failure |
Chronic kidney disease is diagnosed only if the changes persist for more than three months. Stages G1 and G2 without other signs of kidney damage (protein in the urine, changes on ultrasound) are not considered disease.
This calculation is not a diagnosis. eGFR can change temporarily due to dehydration, eating meat, medication and intense exercise. The result should be interpreted by a doctor.