Estimated glomerular filtration rate (eGFR)
Kidney functioneGFR (estimated Glomerular Filtration Rate): Calculated using the CKD-EPI formula based on creatinine level, age, sex, and ethnic background.
Also known as: kidney function, GFR, creatinine clearance estimate
It estimates how much blood your kidneys filter per minute, with normal values typically above 90 ml/min/1.73m². Values below 60 ml/min/1.73m² indicate moderate kidney impairment, while values below 30 ml/min/1.73m² signifies severe impairment.
Reference range
| Level | Range |
|---|---|
| Optimal | above 90 ml/min/1.73m2 |
| Normal | 60 to 89 ml/min/1.73m2 |
| Intermediate | 30 to 59 ml/min/1.73m2 |
| Low | 15 to 30 ml/min/1.73m2 |
| Very low | below 15 ml/min/1.73m2 |
Source: Ahead Health benchmark · LOINC code: 62238-1
* Reference ranges may vary between labs and assays. Always interpret results with your healthcare provider.
Why this matters
eGFR reveals potential kidney health issues before serious symptoms appear. Normal values are typically above 90 ml/min/1.73m². Values below 60 ml/min/1.73m² indicate moderate kidney impairment, while values below 30 ml/min/1.73m² signifies severe impairment. Early warning signs may include fatigue, swelling, or changes in urination.
Monitoring eGFR helps track kidney function over time, supporting lifestyle measures such as blood pressure control, hydration, and avoiding kidney-damaging medications.
How this connects to other biomarkers
- eGFR estimates kidney function from Creatinine; in extremes of muscle mass (sarcopenia, bodybuilders, amputees) estimated Glomerular Filtration Rate (eGFR) - Cystatin C is more accurate.
- eGFR < 60 ml/min/1.73m² for > 3 months defines chronic kidney disease (CKD); stages: G3a (45–59), G3b (30–44), G4 (15–29), G5 (< 15) — each step represents a meaningful loss of filtering capacity.
- Falling eGFR with rising Phosphate, low Calcium, and falling Hemoglobin indicates CKD progression with secondary mineral-bone disorder and anemia of CKD (the kidney also makes the hormone that drives red-cell production).
How often should I test Estimated glomerular filtration rate (eGFR)?
Most adults benefit from checking eGFR once a year as part of kidney screening. With chronic kidney disease, hypertension, or diabetes, retest every three to six months. A sudden drop warrants a confirmatory retest within a few weeks.
At baseline / for screening: Once every 12 months from age 30 as part of a kidney panel. More frequently, every 3 to 6 months, if you have hypertension, type 2 diabetes, chronic kidney disease, or take medication processed through the kidneys.
When monitoring an intervention or change: Retest 2 to 4 weeks after starting a new medication that affects the kidneys (ACE inhibitor, ARB, SGLT2 inhibitor, diuretic, NSAID, certain antibiotics) to confirm stable function. After a meaningful change in blood pressure or diabetes control, retest at 3 months. Hydration on the morning of the draw can shift creatinine-based numbers, so reproduce conditions for reliable trend tracking.
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