eGFRmL/min
Kidney filtration capacity
Also known as: Estimated GFR, Estimated Glomerular Filtration Rate
Typical optimal range
60–200 mL/min
A result of 60–200 mL/min is generally considered within the typical range, though exact reference intervals vary between laboratories, so always interpret your result alongside your lab's own report. These figures are indicative — the range printed on your own lab report is the definitive one for your results.
CKD identification, staging, and management in UK primary and secondary care follow NICE guideline NG203 (Chronic kidney disease: assessment and management).
What is eGFR?
eGFR stands for estimated glomerular filtration rate, a calculated measure of how well your kidneys are filtering waste products from your blood. It is derived from your blood creatinine level — a by-product of normal muscle metabolism — combined with your age and sex, using a validated equation (most UK labs now use the CKD-EPI formula). Because the kidneys' filtration capacity reflects their overall health, eGFR is one of the most useful single markers for detecting and monitoring kidney disease before symptoms appear.
What a high eGFR means
An eGFR above the upper end of the typical range is rarely a cause for concern on its own, but in certain contexts it is worth noting as a prompt to look a little closer.
- Diabetic hyperfiltration. In the early stages of diabetes, the kidneys can work harder than normal, producing a transiently elevated eGFR. This 'hyperfiltration' phase is clinically important because, left unmanaged, it can precede later kidney decline — so it is worth discussing with your GP if you have diabetes.
- High muscle mass. Because eGFR is calculated from creatinine, people with significantly above-average muscle mass (for example, athletes or those doing heavy resistance training) naturally produce more creatinine, which can cause the equation to underestimate filtration capacity and produce an unexpectedly high or variable figure.
- Laboratory or biological variation. A single elevated reading can reflect normal day-to-day biological fluctuation, recent high protein intake, or hydration status rather than a true change in kidney function. Results are most meaningful when interpreted as a trend over time.
An isolated high eGFR in an otherwise healthy person without diabetes or kidney risk factors is rarely clinically significant; your GP will consider the full picture.
What a low eGFR means
An eGFR that falls below 60 mL/min on two or more measurements taken at least 90 days apart is the key threshold used to define chronic kidney disease (CKD) in UK clinical practice — this is the reading that warrants a conversation with your GP.
- Hypertension. Persistently raised blood pressure damages the small blood vessels in the kidneys over time, gradually reducing their ability to filter effectively. High blood pressure is one of the leading causes of CKD in the UK.
- Diabetes. Chronically elevated blood glucose causes structural changes to the kidney's filtering units (glomeruli), making diabetic kidney disease one of the most common causes of reduced eGFR and a key focus of diabetes management in UK primary care.
- Chronic NSAID use and other nephrotoxins. Regular use of anti-inflammatory painkillers such as ibuprofen can reduce blood flow to the kidneys and, over time, cause damage. Certain other medicines and herbal products can also be nephrotoxic, which is why your GP needs to know everything you take regularly.
eGFR also declines gradually with age as a normal physiological process; older adults often have readings below 60 without significant underlying disease, and your GP will interpret your result in the context of your age, symptoms, and trend over time.
Should I be worried?
A single eGFR result — whether slightly low or unexpectedly high — is rarely the whole story. Kidney function can fluctuate with hydration, recent illness, strenuous exercise, or certain medications, which is why UK clinical guidelines define CKD on the basis of a persistently reduced eGFR over at least three months, not a one-off reading. If your result is below 60, or if you notice a downward trend across repeated tests, it is sensible to speak to your GP rather than wait. They are likely to repeat the test, check urine for protein (a key early sign of kidney damage), review your blood pressure, and look at other kidney-related markers such as urea and electrolytes — building a fuller picture before deciding whether any action is needed.
What actually helps
While no lifestyle change can reverse established kidney disease, there is good evidence that the following steps help protect kidney function and slow its decline.
- Blood pressure control. Keeping blood pressure within a healthy range is the single most important modifiable factor for protecting kidney function. NICE recommends a target below 140/90 mmHg in most people with CKD, and lower if significant protein is present in the urine. Even modest reductions in blood pressure meaningfully slow kidney decline.
- Manage blood glucose if you have diabetes. Good glycaemic control — aiming for HbA1c targets agreed with your GP or diabetes team — significantly reduces the risk of diabetic kidney disease progressing. Certain diabetes medicines (SGLT2 inhibitors) also have a direct kidney-protective effect and are now recommended in UK guidance.
- Avoid chronic NSAID use. Using ibuprofen or similar anti-inflammatory medicines occasionally is unlikely to cause lasting harm, but taking them regularly without medical supervision can cumulatively reduce kidney blood flow. Discuss alternatives with your GP or pharmacist if you need regular pain relief.
- Stay well hydrated. Adequate fluid intake supports kidney perfusion and helps prevent kidney stones, which can damage kidney tissue over time. For most adults, around 6–8 glasses of fluid a day is a reasonable guide, though needs vary with climate, activity, and health conditions.
There is good supporting evidence that the following dietary patterns and foods help maintain healthy blood pressure and reduce metabolic stress on the kidneys.
Vegetables and fruit
A diet rich in plant foods is consistently associated with lower blood pressure and better cardiovascular and kidney outcomes; potassium from wholefood plant sources may be protective, though those with confirmed CKD should take individual advice on high-potassium foods.
Wholegrains
Wholegrains support blood pressure control and help maintain a healthy weight, both of which reduce the metabolic burden on the kidneys over time.
Oily fish
Regular consumption of oily fish such as salmon, mackerel, or sardines provides omega-3 fatty acids, which have anti-inflammatory properties and are associated with lower blood pressure and reduced cardiovascular risk — a major concern in CKD.
Reduced sodium intake
Excess dietary salt raises blood pressure directly; reducing salt intake to less than 6 g per day (as recommended by the NHS) is one of the most evidence-backed ways to protect kidney and cardiovascular health.
Legumes and pulses
Beans, lentils, and chickpeas provide plant-based protein and fibre with a lower phosphate and acid load than animal protein, which may be gentler on kidney filtration capacity over time — an area of active research in renal nutrition.
Low-fat dairy or fortified alternatives
Moderate dairy intake provides calcium and protein without the high sodium of processed foods, and observational data link adequate calcium intake with a lower risk of kidney stones in the general population.
Track your own eGFR
Upload a lab PDF and Better Days trends eGFR over time, flags it when it drifts, and suggests foods that help.
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Sources & further reading
These are reputable UK health resources for further reading. This page is written to be consistent with their guidance but is not a substitute for them.
For information only — not medical advice, and not individually reviewed by a clinician. Reference ranges vary by lab and individual. Discuss any results with a qualified clinician before making changes.