eGFR
Also known as: Estimated Glomerular Filtration Rate
What Does eGFR Measure?
eGFR, or Estimated Glomerular Filtration Rate, measures how well your kidneys are filtering waste products, excess fluids, and toxins from your blood. Specifically, it estimates the volume of blood your kidneys' tiny filtering units — called glomeruli — can clean per minute, expressed in milliliters per minute per 1.73 square meters of body surface area (mL/min/1.73m²). The value is calculated using a mathematical equation that factors in your blood creatinine level along with variables such as age, sex, and sometimes race, with the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation being the most widely used today.
Why Does eGFR Matter?
eGFR is one of the most critical indicators of kidney health and is used to detect, stage, and monitor chronic kidney disease (CKD). A declining eGFR can signal progressive kidney damage even before noticeable symptoms appear, making it an invaluable early warning tool. Healthcare providers use eGFR to determine how aggressively to treat underlying conditions like diabetes and hypertension, to adjust medication dosages that are cleared by the kidneys, and to determine when a patient may need dialysis or a kidney transplant. Tracking eGFR over time — its rate of decline — is often more informative than a single measurement, as it reveals the trajectory of kidney function.
Normal Ranges
Males
60–120 mL/min/1.73m² (≥60 is generally considered normal; values ≥90 indicate optimal kidney function)
Females
60–110 mL/min/1.73m² (≥60 is generally considered normal; values ≥90 indicate optimal kidney function)
Children
Varies by age; normal eGFR in children is typically ≥90 mL/min/1.73m², with infants starting lower and reaching adult values by age 2
Causes of High Levels
- Pregnancy — increased blood volume and cardiac output can raise eGFR, a normal physiological adaptation
- High protein diet — excess dietary protein increases creatinine production and can transiently elevate calculated eGFR
- Hyperfiltration in early diabetes (Type 1 or Type 2) — kidneys work harder in the early stages, temporarily boosting filtration before damage sets in
- Obesity — increased metabolic demand and renal blood flow can elevate filtration rates
- High fluid intake or IV fluid administration — expanded plasma volume increases renal perfusion and filtration
- Certain medications such as ACE inhibitors or NSAIDs affecting renal blood flow dynamics in some contexts
Causes of Low Levels
- Chronic kidney disease (CKD) — progressive loss of functioning nephrons is the most common cause of persistently low eGFR
- Diabetes mellitus — diabetic nephropathy is a leading cause of kidney damage and declining eGFR worldwide
How to Improve Your eGFR
Diet
- Reduce sodium intake to less than 2,300 mg per day (ideally under 1,500 mg if CKD is present) to lower blood pressure and reduce kidney workload
- Moderate protein consumption — aim for 0.6–0.8 g/kg body weight per day if CKD is diagnosed; excessive protein accelerates kidney decline
- Limit phosphorus-rich foods such as processed meats, dark colas, and fast food, which impair kidney function in CKD
- Increase plant-based foods (fruits, vegetables, whole grains) which are associated with slower CKD progression and lower acid load on kidneys
- Stay well hydrated with adequate water intake (approximately 2–3 liters per day unless fluid restriction is advised) to maintain good renal perfusion
Supplements
- Omega-3 fatty acids (1,000–2,000 mg EPA/DHA daily) — may reduce proteinuria and have anti-inflammatory effects on kidney tissue
- Vitamin D3 (1,000–2,000 IU daily, under physician guidance) — CKD impairs vitamin D activation; supplementation may help reduce kidney disease progression
- Coenzyme Q10 (100–200 mg daily) — antioxidant properties may support kidney cell health and reduce oxidative stress
- Bicarbonate supplementation (as prescribed by a doctor) — correcting metabolic acidosis common in CKD may slow its progression
Related Biomarkers
Frequently Asked Questions
What eGFR level is considered kidney failure?
An eGFR below 15 mL/min/1.73m² is classified as Stage 5 CKD, also known as kidney failure or end-stage renal disease (ESRD). At this level, the kidneys can no longer adequately filter the blood, and patients typically require dialysis or a kidney transplant to survive. Stage 4 CKD (eGFR 15–29) is considered severely decreased kidney function and often involves preparation for renal replacement therapy.
Can eGFR improve or go back to normal?
Yes, in some cases eGFR can improve, particularly if the underlying cause is treatable. For example, eGFR can recover after acute kidney injury caused by dehydration, infection, or medication toxicity once the trigger is addressed. In chronic kidney disease, it's often difficult to significantly reverse the decline, but slowing progression — or even modest improvements — is achievable with aggressive blood pressure control, blood sugar management, dietary changes, and appropriate medications such as ACE inhibitors, ARBs, or SGLT2 inhibitors.
What is the difference between eGFR and creatinine?
Creatinine is a waste product produced by muscle metabolism that is filtered by the kidneys. eGFR is calculated using the creatinine level along with factors like age and sex to estimate overall kidney filtration capacity. While a high creatinine level suggests poor kidney function, eGFR provides a more standardized and clinically meaningful number. For example, an elderly woman and a young muscular man might have the same creatinine level but very different eGFR values because muscle mass — which determines creatinine production — differs between them.