eGFR Blood Test: What Your Kidney Filtration Number Means
Order BUN/Creatinine Ratio TestQuick Answer
eGFR stands for estimated glomerular filtration rate, a calculated number that estimates how much blood your kidneys filter each minute. An eGFR blood test helps show how well the kidneys are working.
Key Takeaways
- eGFR estimates the glomerular filtration rate, a measure of how much blood the kidneys filter each minute.
- A normal eGFR is generally 90 mL/min/1.73 m2 or higher in healthy adults.
- eGFR is calculated from creatinine along with age and sex, not measured directly.
- An eGFR below 60 for three months or more can indicate chronic kidney disease.
- eGFR normally declines with age, so a lower value can be expected in older adults.
- A kidney panel that includes eGFR commonly costs about $29 to $79 through direct-access labs.
What Is eGFR?
eGFR stands for estimated glomerular filtration rate. It is a calculated number that estimates how much blood your kidneys filter each minute, and it is the main way clinicians gauge kidney function. The estimated part matters: eGFR is not measured directly. It is worked out from your blood creatinine level together with your age and sex, using a formula that accounts for average muscle mass.
Kidneys filter waste and extra fluid from the blood and send it out as urine. The glomeruli are the tiny filtering units that do this work, and the filtration rate is a proxy for how many of them are working well. A falling eGFR suggests the kidneys are losing filtering capacity. Because the calculation depends on muscle mass, people with very high or very low muscle mass can get a number that needs extra interpretation.
Laboratories often report eGFR alongside the name of the formula used, and a result can be shown as greater than 60 rather than a precise number when kidney function is normal.
Normal eGFR Range
eGFR is reported in milliliters per minute per 1.73 square meters (mL/min/1.73 m2). Because the formula includes age, the normal value falls with age, so a number that looks low for a young adult can be expected in an older one. Common bands are:
| eGFR | Typical interpretation |
|---|---|
| 90 or higher | Normal kidney function in most healthy adults |
| 60 to 89 | Mildly reduced; often normal with age if no other signs |
| 45 to 59 | Mildly to moderately reduced |
| 30 to 44 | Moderately reduced |
| 15 to 29 | Severely reduced |
| Below 15 | Kidney failure range; needs urgent care |
A single low value is not a diagnosis. Clinicians look for a reduced eGFR that persists for three months or more, along with other signs such as protein in the urine, before calling it chronic kidney disease. A temporary illness, dehydration, or a heavy protein meal can all shift the number for a short time.
What Low eGFR Means
A low eGFR means the kidneys are filtering less blood than expected for your age and sex. Early on there are often no symptoms at all, which is why blood testing matters. As filtering falls further, waste products build up and can cause fatigue, swollen ankles, puffiness around the eyes, poor appetite, and changes in urination.
An eGFR below 60 that lasts three months or longer is one of the criteria used to identify chronic kidney disease. The number is a starting point for a conversation with a clinician, not a verdict on its own, because it must be read with urine protein, blood pressure, and the trend over time.
A downward trend across several tests is often more informative than any single value, which is why repeat testing matters when the first result is low.
Causes of Reduced eGFR
- Diabetes, the most common cause of kidney disease in adults
- High blood pressure, which damages the small filtering vessels over time
- Dehydration or a temporary drop in blood flow, which can lower eGFR briefly
- Certain medications, including some pain relievers and other drugs
- Glomerular diseases and inherited conditions such as polycystic kidney disease
- Age, since filtration naturally declines over the years
Some causes are reversible and others are progressive, so the result is always read with the trend over time and with other tests rather than from one number. Keeping blood sugar and blood pressure in range is the main way to protect kidney function when a risk factor is present.
How eGFR Fits Into a Panel
eGFR is not ordered on its own in most cases. It is calculated from a creatinine result, so it appears automatically when creatinine is measured. Creatinine is part of a basic metabolic panel and a comprehensive metabolic panel (CMP), and it is often checked with BUN in a BUN-to-creatinine ratio.
A urine albumin test is frequently added, because protein leaking into urine is an early sign of kidney damage that eGFR alone can miss. Together, the blood and urine markers give a fuller picture than either one by itself.
Because eGFR depends on creatinine, anything that changes creatinine for reasons other than kidney function, such as muscle mass or certain medicines, can shift the estimate.
When to Test and How to Order
Checking kidney function is reasonable if you have diabetes, high blood pressure, a family history of kidney disease, or take medicines that can affect the kidneys. It is also common as part of routine blood work.
Direct-access lab testing lets you order a kidney function panel or a CMP online without a doctor visit. After checkout you receive a requisition and visit a local collection site for a blood draw with photo ID. Fasting is usually not required for kidney testing alone, though a CMP may be done fasting. Results typically return within one to two business days.
How Much Does an eGFR or Kidney Panel Cost?
A kidney function panel that includes creatinine and eGFR commonly costs about $29 to $79 through direct-access labs. A basic metabolic panel often runs about $29 to $59, and a comprehensive metabolic panel about $49 to $99. Prices vary by laboratory and city, and a small collection fee may apply. Because no insurance claim is filed, the checkout price is generally the full price.
Frequently Asked Questions
What is a normal eGFR level?
A normal eGFR is generally 90 mL/min/1.73 m2 or higher in healthy adults, though the value naturally declines with age. Use the range on your own report.
What does a low eGFR mean?
A low eGFR means the kidneys are filtering less blood than expected. An eGFR below 60 that persists for three months or more is one criterion for chronic kidney disease, but it needs clinical context.
How is eGFR calculated?
eGFR is estimated from blood creatinine along with your age and sex. It is not measured directly, so it is an estimate rather than an exact filtration rate.
Do I need to fast for an eGFR test?
Fasting is usually not required for kidney testing alone. If your eGFR is part of a comprehensive metabolic panel, that panel may call for fasting.
Can I order an eGFR test without a doctor?
Yes. Direct-access lab testing lets you order a kidney function panel or a metabolic panel online and visit a local collection site without a physician order.
Where to Get This Test
Related Guides
Sources
This guide is reviewed for sourcing accuracy against the references listed above. It is educational information, not medical advice. Always consult a qualified healthcare provider about your own results and care.
Ready to get tested? Order online through our partner and visit a local lab near you. No doctor's order or insurance required.
Order BUN/Creatinine Ratio TestReviewed by the LabAppointments Editorial Team
Our team researches and fact-checks all content to ensure accuracy. We update guides regularly to reflect current testing options, pricing, and laboratory accreditation standards.