What is estimated glomerular filtration rate (eGFR)?
Estimated glomerular filtration rate, or eGFR, is a calculated marker that estimates how well your kidneys are filtering waste from your blood. It is worked out from a blood test measuring creatinine (a waste product from normal muscle activity), combined with your age and sex. Results are reported in millilitres per minute per 1.73 m² (mL/min/1.73m²) in Australia.
Because your kidneys quietly clear waste, balance fluids and electrolytes, regulate blood pressure and support red blood cell and vitamin D production, eGFR is one of the most useful markers for tracking kidney health over time. It is part of most routine health checks and forms the basis of the Kidney Health Check recommended by RACGP and Kidney Health Australia. You can read more in our complete guide to the eGFR blood test.
Why does eGFR matter for long-term health and wellbeing?
Chronic kidney disease (CKD) is common in Australia, affecting around one in ten adults, yet many people are unaware because early CKD rarely causes symptoms. Left unmonitored, declining kidney function can raise cardiovascular risk significantly, contribute to anaemia, bone health issues, high blood pressure and electrolyte problems, and eventually progress to kidney failure. eGFR is one of the earliest ways to spot this quiet decline, often years before symptoms appear.
Beyond kidney disease itself, eGFR is closely tied to metabolic health, cardiovascular risk and healthy ageing. Diabetes and high blood pressure are the two leading causes of CKD in Australia, and both are largely preventable through lifestyle and early treatment. Tracking eGFR gives you an actionable signal, and it is one of the kidney markers Vively includes as part of its baseline health testing.
What is an ideal eGFR level?
In Australia, eGFR is generally interpreted as follows: 90 mL/min/1.73m² or above is considered normal, 60 to 89 is mildly decreased (which can still be normal in older adults without other signs of kidney damage), 45 to 59 is stage G3a CKD, 30 to 44 is G3b, 15 to 29 is G4 and below 15 is kidney failure (G5). Australian labs typically report anything above 90 as simply ">90" and give an actual value below that. A diagnosis of CKD generally requires an eGFR under 60 for three months or more, or an eGFR above 60 alongside other signs of kidney damage such as protein in the urine.
There is no single perfect number. Interpretation depends on your age, sex, muscle mass, hydration status, medications and other markers, and eGFR naturally declines with age by roughly 1 mL/min per year after 40. A trend over time is usually more meaningful than a single reading.
What influences eGFR levels?
Age is one of the biggest natural influences, since kidney filtration gradually declines over life, particularly after 40. Muscle mass affects results too, because eGFR is calculated from creatinine, which comes from muscle turnover. Very muscular people can have slightly lower eGFR without any kidney problem, while people with low muscle mass may have a falsely reassuring higher eGFR.
Diet, hydration and recent activity can also shift results, as high protein intake, cooked meat, creatine supplements and intense exercise in the days before testing can raise creatinine. Medications influence eGFR too, including NSAIDs (such as ibuprofen and naproxen with long-term or heavy use), ACE inhibitors, angiotensin receptor blockers, some antibiotics, contrast dye used in imaging and certain chemotherapy drugs. Diabetes, high blood pressure, autoimmune diseases and recurrent kidney infections are major medical influences.
What are the symptoms of low eGFR?
Early kidney disease usually has no symptoms, which is one of the main reasons routine testing matters. When kidney function drops further, symptoms can include ongoing fatigue, swelling in the ankles or around the eyes, changes in urination (more or less frequent, foamy urine, or dark urine), itchy skin, poor appetite, nausea, muscle cramps and difficulty concentrating. High blood pressure and worsening blood sugar control are also common signals.
More advanced kidney disease can cause more noticeable symptoms such as shortness of breath, persistent nausea, weight loss, restless legs, easy bruising and, in severe cases, confusion. Because early symptoms overlap with many other conditions, testing is far more reliable than trying to interpret how you feel. Any of these symptoms combined with a low or falling eGFR should be reviewed by your GP.
What causes low eGFR?
The two most common causes of low eGFR in Australia are diabetes (where high blood sugar damages the small blood vessels in the kidneys) and high blood pressure (which strains the kidney's filtering units over time). Insulin resistance and metabolic syndrome are important upstream drivers of both, and our guide on how to tell if you are insulin resistant explores this connection. Other causes include autoimmune kidney diseases, polycystic kidney disease, recurrent urinary tract infections, kidney stones and long-term use of nephrotoxic medications.
Temporary drops in eGFR can occur with acute illness, dehydration, severe infections, heart failure, contrast dye used in scans, or the introduction of certain blood pressure and heart medications. Genetics, older age, obesity, smoking and Aboriginal or Torres Strait Islander heritage all increase the risk of kidney disease. A trend of declining eGFR over months or years is often more meaningful than a single reading.
Is a high eGFR ever a concern?
A high eGFR in a healthy adult is usually reassuring and reflects good kidney function. Because most Australian labs simply report anything above 90 as ">90", extremely high results are rarely visible on routine testing. In some cases, hyperfiltration (a genuinely high filtration rate) can occur in early diabetes, obesity or pregnancy, and may be an early warning sign of kidney stress rather than a positive.
Very high eGFR can also occur when creatinine is low due to reduced muscle mass, malnutrition, chronic illness or amputation, which may make kidney function look better than it really is. This is one reason cystatin C is sometimes used as a second marker of kidney function, particularly in older adults or those with low muscle mass. As with any marker, context matters more than a single high number.
What does it mean if eGFR is outside the optimal range?
A low eGFR suggests your kidneys are not filtering as well as expected, though it does not diagnose any specific condition on its own. Mildly low results are common, particularly in older adults, and are usually monitored rather than acted on immediately. Persistently low eGFR (particularly under 60 for three months or more) or a rapidly falling eGFR is a signal to investigate further.
A very high eGFR is usually not a concern, but in specific situations such as early diabetes or obesity, hyperfiltration can be an early sign of kidney strain. Patterns over time, alongside related markers such as urinary albumin, are far more informative than any single reading.
Can eGFR be normal but something still be wrong?
Yes, a normal eGFR does not always rule out kidney disease. Early kidney damage often shows up as protein or albumin in the urine (albuminuria) before eGFR starts to fall, which is why urinary ACR is such an important companion test. Structural kidney problems such as polycystic kidney disease, kidney stones or tumours may also exist even when eGFR looks normal.
Because eGFR is calculated from creatinine, results can be misleading in people with unusually high or low muscle mass, malnutrition, pregnancy, cirrhosis or after significant weight change. Cystatin C, which is not affected by muscle mass, may give a more accurate estimate in these situations. This is why eGFR is best interpreted alongside a urinary ACR, blood pressure, urine tests and, where appropriate, imaging or specialist input.
What other markers should be checked with eGFR?
Serum creatinine is the primary input into eGFR and is usually reported alongside it. Urinary albumin to creatinine ratio (ACR) is the single most important companion, since protein in the urine is often the earliest sign of kidney damage and can occur even when eGFR looks normal. Urea (BUN) adds further insight, particularly around hydration, protein intake and kidney function.
Electrolytes such as sodium, potassium, chloride and bicarbonate reflect how well the kidneys are managing fluid and mineral balance, and phosphate, calcium, vitamin D and parathyroid hormone become increasingly important as kidney function declines. HbA1c, fasting glucose, fasting insulin and lipids help identify metabolic drivers of kidney disease, and blood pressure is essential context. Uric acid and hs-CRP add further insight, and you can see the full set of markers Vively looks at through our tests page and shop tests page.
How can you improve eGFR to a healthier level?
Kidney function often cannot be fully restored once lost, but you can slow decline and support long-term kidney health through consistent lifestyle change. That usually means managing blood pressure and blood sugar closely, prioritising a diet rich in vegetables, legumes, whole grains, oily fish and healthy fats, while reducing ultra-processed foods, sugary drinks and excess salt. Adequate hydration, regular movement, quitting smoking and moderating alcohol all support kidney health, as does maintaining a healthy body composition.
Reviewing medications with your GP or pharmacist matters, particularly regular NSAID use, and being cautious with new supplements or high-protein programs when kidney function is reduced. For diagnosed CKD, medications such as ACE inhibitors, angiotensin receptor blockers or newer kidney-protective medications may be recommended. Not every marker can or should be self-optimised, and Vively's how it works page explains how testing, monitoring and dietitian coaching combine to support kidney and overall health.
When does eGFR need medical review?
See your GP if your eGFR is persistently below 60, has dropped significantly since your last test, or is accompanied by protein in the urine, high blood pressure, changes in urination, swelling or ongoing fatigue. Any sudden or unexplained drop in eGFR should be reviewed promptly, as acute kidney injury can develop quickly and may be reversible with early treatment. A very low eGFR (below 30) warrants specialist review with a nephrologist.
Clinical input is particularly important if you have diabetes, high blood pressure, cardiovascular disease, polycystic kidney disease, autoimmune conditions, recurrent UTIs, gout, a family history of kidney disease or if you are Aboriginal or Torres Strait Islander. Pregnancy, planning pregnancy, starting or changing medications that affect the kidneys, and preparing for scans that use contrast dye are all reasons to check in. eGFR should never be self-diagnosed, as it is one piece of a bigger clinical picture your GP or nephrologist can help you interpret.
How does Vively help you understand eGFR?
eGFR is one of the kidney markers included in the Vively Baseline Health Check, alongside creatinine, urea, electrolytes, uric acid, metabolic markers such as HbA1c and fasting glucose, cardiovascular markers, liver enzymes, inflammation markers and more than 60 other biomarkers in total. Rather than looking at eGFR in isolation, Vively interprets it in context with your other results, symptoms, medications and lifestyle. Where relevant, real-world glucose data from a continuous glucose monitor adds another layer of insight into how metabolic health is affecting your kidneys.
A registered nurse reviews your results with you one on one, and accredited practising dietitians support the changes that follow. Because your markers are retested over time, you can see how blood pressure, blood sugar, nutrition and lifestyle are actually shifting your kidney and broader health profile rather than guessing. Start at the Vively homepage or explore the full range of tests in the Vively shop.
References
- Royal College of Pathologists of Australasia. RCPA Manual: Creatinine and eGFR. https://www.rcpa.edu.au/Manuals/RCPA-Manual/Pathology-Tests/C/Creatinine
- Kidney Health Australia. Chronic kidney disease (CKD) management in primary care. https://kidney.org.au/health-professionals/ckd-management-handbook
- Kidney Health Australia. Kidney Health Check. https://kidney.org.au/
- Royal Australian College of General Practitioners. Guidelines for preventive activities in general practice (Red Book). https://www.racgp.org.au/clinical-resources/clinical-guidelines/key-racgp-guidelines/view-all-racgp-guidelines/red-book
- Healthdirect Australia. Kidney function tests. https://www.healthdirect.gov.au/kidney-function-tests
- Better Health Channel, Victorian Department of Health. Kidneys. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/kidneys
- Australian Institute of Health and Welfare. Chronic kidney disease. https://www.aihw.gov.au/reports/chronic-kidney-disease/chronic-kidney-disease/
- Inker LA, Eneanya ND, Coresh J, et al. New creatinine and cystatin C based equations to estimate GFR without race. New England Journal of Medicine. 2021;385(19):1737 to 1749.
- Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney International. 2024;105(4S):S117 to S314.
- Levey AS, Coresh J. Chronic kidney disease. The Lancet. 2012;379(9811):165 to 180.
- Cleveland Clinic. Estimated glomerular filtration rate (eGFR). https://my.clevelandclinic.org/health/diagnostics/21593-estimated-glomerular-filtration-rate-egfr
- Mayo Clinic. Chronic kidney disease. https://www.mayoclinic.org/diseases-conditions/chronic-kidney-disease/symptoms-causes/syc-20354521
- National Institute of Diabetes and Digestive and Kidney Diseases. Estimating glomerular filtration rate. https://www.niddk.nih.gov/health-information/professionals/clinical-tools-patient-management/kidney-disease/laboratory-evaluation/glomerular-filtration-rate/estimating
.png)
.png)
.svg)
