eGFR converts your creatinine, age and sex into an estimate of how much blood your kidneys filter each minute. It is the number that defines every stage of chronic kidney disease.
Standard range versus optimal range
| Framework | eGFR value | Source |
|---|---|---|
| Normal kidney function | 90 or above | KDIGO |
| G2, mildly decreased | 60-89 | KDIGO |
| G3, moderately decreased | 30-59 | KDIGO |
| G4-G5, severe to failure | below 30 | KDIGO |
When it runs high
An eGFR above 120 is usually hyperfiltration, seen in early diabetes, obesity and pregnancy, or simply reflects low muscle mass making creatinine deceptively low. High-normal is healthy, sustained hyperfiltration is a warning.
- Early diabetes hyperfiltration
- Pregnancy, physiological
- Low muscle mass lowering creatinine
- Obesity-related hyperfiltration
When it runs low
A persistent eGFR below 60 for three months defines chronic kidney disease by KDIGO criteria. Because creatinine tracks muscle, very muscular people read falsely low and frail elderly people falsely high, which is where cystatin C earns its place.
- Chronic kidney disease from diabetes or hypertension, the commonest pair
- Age-related decline, roughly 1 unit per year after 40
- Acute kidney injury, transient
- Dehydration, transient
- Glomerular and interstitial diseases
One number that stages a silent disease
Kidneys fail quietly, and eGFR exists to catch them before symptoms. The CKD-EPI equation, published by Levey and colleagues in 2009 and refined since, turns a routine creatinine into a filtration estimate, and KDIGO built the entire global staging system on it, G1 through G5, combined with urine albumin. A value of 58 is not 2 percent worse than 62, it crosses a threshold that changes monitoring, medication doses and cardiovascular risk management.
The muscle mass trap
eGFR inherits creatinine’s weakness, it reflects muscle as much as kidney. A bodybuilder with healthy kidneys can read 55 and get mislabeled with CKD, while an elderly woman with little muscle can read 75 with half her kidney function gone. When the number clashes with the picture, cystatin C, a muscle-independent marker, settles the argument, and the combined creatinine-cystatin equation is the most accurate bedside estimate available.
Slope matters more than level
A single eGFR is a snapshot, the trajectory is the story. Losing 1 unit per year is aging, losing 3 to 5 per year is a disease in motion. Plotting values over time separates stable age-related decline, which rarely reaches failure, from progressive disease that needs nephrology. Blood pressure control, glucose control and avoiding long-term NSAID overuse remain the proven brakes on the slope.
Related calculators
Related biomarkers Creatinine · Cystatin C · Urea · Albumin