eGFR (estimated glomerular filtration rate): what it means
What it measures
An eGFR (estimated glomerular filtration rate) is a blood test that checks how well your kidneys are working by estimating how much blood your kidneys filter each minute. It is calculated from your blood creatinine level — a normal waste product made when you use your muscles — together with your age, sex, and often your weight and height, entered into a standard formula. In some cases it is estimated using a blood protein called cystatin C instead, because cystatin C levels are not affected by muscle size, age, or diet. According to MedlinePlus, an eGFR is a more accurate way to measure kidney health than a creatinine level alone, and it can help show how serious kidney disease is. It is an estimate: MedlinePlus notes an eGFR "isn't a perfect test and may not always reflect kidney damage."
Why it’s ordered
Early kidney disease often causes no symptoms, so an eGFR is commonly done as part of a routine check-up or to screen people at higher risk of kidney disease. Per MedlinePlus, higher-risk groups include people with diabetes, high blood pressure, heart disease, a family history of kidney disease, and those who are older, smoke, or have obesity. It may also be ordered when someone has possible symptoms (such as swelling in the legs, feet, ankles, hands, or face; urinating more or less often than usual; fatigue; muscle cramps; itchy or dry skin; or nausea and loss of appetite), and it is used to monitor kidney function over time in people already diagnosed with kidney disease.
General reference range
Reference ranges are general and vary by the laboratory, the equation used, and by your age, sex, and body factors — your own lab report and your clinician's interpretation are what apply to you, not any single number listed here. MedlinePlus does not frame results as one fixed cutoff: in general a normal eGFR means you probably don't have kidney disease; an eGFR below normal or low may mean you have kidney disease; and a very low eGFR may mean kidney failure. For general orientation only, MedlinePlus's Medical Encyclopedia describes eGFR in units of mL/min/1.73 m2, with normal results roughly in the 90–120 range, and NIH's NIDDK states that a GFR of 60 or more is in the normal range, a GFR below 60 may mean kidney disease (chronic kidney disease is generally considered when the value stays below 60 for three or more months), and a GFR of 15 or less is called kidney failure. A single result can also be abnormal without kidney damage, so a low value is usually confirmed and interpreted over time rather than from one test.
If it’s high
A higher or normal eGFR is generally the reassuring direction and usually suggests the kidneys are filtering well. A high eGFR is not typically treated as a problem on its own. This is general information and not a diagnosis.
If it’s low
A below-normal or low eGFR may suggest reduced kidney function and can be seen with kidney disease; a very low eGFR may suggest kidney failure. These are general possible associations, not a diagnosis or a complete list — MedlinePlus notes it is also possible to have an abnormal result even if you don't have kidney damage. A low result is interpreted in the context of your overall health, other test results, and whether it stays low over time. Your eGFR should be interpreted by your health care provider, who considers your full medical picture and how your numbers change over time to decide what your result means for you. This is general information, not medical advice.
A result is not a diagnosis
Reference ranges vary by laboratory, age, sex, and method — the range on your own report is what applies to you. A single value out of range doesn’t confirm any condition; your clinician interprets it alongside your symptoms, history, and other results. This page is general information, not medical advice.
Medicines that can move this result
It blocks the tubule's disposal of creatinine, so the calculated eGFR falls while the kidney's real filtering rate stays the same. The label states this outright.
Source ↗It blocks OCT2, the transporter that normally moves creatinine from blood into urine, so creatinine rises and calculated eGFR drops without real kidney damage. The label reports the shift appears within the first 4 weeks and then stays stable, averaging a 0.15 mg/dL change from baseline at 96 weeks.
Source ↗By stopping the tubules from secreting creatinine into urine it raises the blood creatinine that the eGFR formula reads, so the estimate drops even though filtration has not changed. The effect reverses when the drug is stopped.
Source ↗It competes with creatinine for the same tubular exit, nudging creatinine up and the calculated eGFR down. The label says explicitly that this does not signify deteriorating kidney function.
Source ↗This SGLT2 inhibitor raises serum creatinine and lowers eGFR, with larger changes in people who already have reduced kidney function. In a long-term outcome trial the change reversed after treatment was stopped, which the label says points to an acute blood-flow effect inside the kidney rather than damage.
Source ↗Because it raises serum creatinine, the eGFR calculated from that number falls. The label says the increases tend to return to baseline after the drug is stopped and that the clinical significance is unknown, while advising kidney-function monitoring in people at risk.
Source ↗This transplant anti-rejection drug can harm the kidney by constricting its blood vessels and by direct toxicity to the tubules, which raises creatinine and lowers eGFR. The label calls the acute form usually reversible and tells prescribers to consider reducing or pausing the dose when creatinine is up and blood levels are above the recommended range.
Source ↗By reducing the prostaglandins that keep blood flowing to the kidney it can cut filtration. The label names those at greatest risk: impaired kidney function, heart failure, liver dysfunction, anyone taking a diuretic or ACE inhibitor, and the elderly. Stopping the NSAID is usually followed by recovery to the pretreatment state.
Source ↗Do not stop a prescribed medicine over a lab number. These are recognised associations, not a finding about your result — your value may have nothing to do with any medicine you take, and the list is not complete. Bring it to whoever prescribed the drug; they can weigh it against why you are taking it.
Frequently asked
- What does the eGFR (estimated glomerular filtration rate) test measure?
- An eGFR (estimated glomerular filtration rate) is a blood test that checks how well your kidneys are working by estimating how much blood your kidneys filter each minute. It is calculated from your blood creatinine level — a normal waste product made when you use your muscles — together with your age, sex, and often your weight and height, entered into a standard formula. In some cases it is estimated using a blood protein called cystatin C instead, because cystatin C levels are not affected by muscle size, age, or diet. According to MedlinePlus, an eGFR is a more accurate way to measure kidney health than a creatinine level alone, and it can help show how serious kidney disease is. It is an estimate: MedlinePlus notes an eGFR "isn't a perfect test and may not always reflect kidney damage."
- What is a normal eGFR (estimated glomerular filtration rate) range?
- Reference ranges are general and vary by the laboratory, the equation used, and by your age, sex, and body factors — your own lab report and your clinician's interpretation are what apply to you, not any single number listed here. MedlinePlus does not frame results as one fixed cutoff: in general a normal eGFR means you probably don't have kidney disease; an eGFR below normal or low may mean you have kidney disease; and a very low eGFR may mean kidney failure. For general orientation only, MedlinePlus's Medical Encyclopedia describes eGFR in units of mL/min/1.73 m2, with normal results roughly in the 90–120 range, and NIH's NIDDK states that a GFR of 60 or more is in the normal range, a GFR below 60 may mean kidney disease (chronic kidney disease is generally considered when the value stays below 60 for three or more months), and a GFR of 15 or less is called kidney failure. A single result can also be abnormal without kidney damage, so a low value is usually confirmed and interpreted over time rather than from one test.
- What does a high result mean?
- A higher or normal eGFR is generally the reassuring direction and usually suggests the kidneys are filtering well. A high eGFR is not typically treated as a problem on its own. This is general information and not a diagnosis.
- What does a low result mean?
- A below-normal or low eGFR may suggest reduced kidney function and can be seen with kidney disease; a very low eGFR may suggest kidney failure. These are general possible associations, not a diagnosis or a complete list — MedlinePlus notes it is also possible to have an abnormal result even if you don't have kidney damage. A low result is interpreted in the context of your overall health, other test results, and whether it stays low over time. Your eGFR should be interpreted by your health care provider, who considers your full medical picture and how your numbers change over time to decide what your result means for you. This is general information, not medical advice.
Other lab tests
Sources
General reference, not medical advice, and not a substitute for your clinician. Lab reference ranges and interpretation depend on the laboratory and on your individual situation — discuss your results with a licensed healthcare professional.