Glossary term
eGFR
Also known as: Estimated Glomerular Filtration Rate, GFR
Part of: Kidney Function Tests
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An estimate of how well your kidneys are filtering blood, calculated from your creatinine.
Medipher explains medical wording in plain English — it does not diagnose or replace a clinician. If this is a medical emergency, call your local emergency number immediately.
Simple visual explanation
What is this?
eGFR stands for estimated Glomerular Filtration Rate — an estimate of how much blood your kidneys filter every minute.
It's calculated from your creatinine result together with your age and sex. It gives a clearer picture of kidney function than creatinine alone.
eGFR is an estimate, not a direct measurement. Small changes between tests are common and usually not significant.
It's reported as mL/min/1.73m² — a measurement adjusted for average adult body size.
Why is it important?
eGFR is the main number used to classify kidney health and to spot chronic kidney disease (CKD) early, before symptoms appear.
It's also used to check that medications processed by the kidneys are dosed safely.
Trends over months and years matter more than any single result. A stable eGFR is often reassuring, even if slightly reduced.
Where you'll see it: U&E blood test panels, alongside creatinine.
How doctors use this result
Clinicians may use this result to:
- Classify kidney function and screen for chronic kidney disease.
- Guide safe dosing of medications cleared by the kidneys.
- Monitor conditions such as diabetes and high blood pressure that affect the kidneys.
- Decide when to refer to a kidney specialist.
What's the normal range?
| G1 — normal or high | 90 or over mL/min/1.73m² |
| G2 — mildly reduced | 60–89 mL/min/1.73m² |
| G3a — mildly to moderately reduced | 45–59 mL/min/1.73m² |
| G3b — moderately to severely reduced | 30–44 mL/min/1.73m² |
| G4 — severely reduced | 15–29 mL/min/1.73m² |
| G5 — kidney failure | under 15 mL/min/1.73m² |
These categories come from UK NICE guidance (NG203) and other systems use similar bands. A single eGFR result does not by itself mean chronic kidney disease: in UK NICE guidance, a new eGFR below 60 ml/min/1.73 m² in an adult who has not previously been tested should be repeated within 2 weeks. This helps confirm the result and check for causes of an acute fall in kidney function. An eGFR of 60 or above is not classed as kidney disease unless there are other signs of kidney damage.
Kidney function slowly declines with age, so a value of 60–89 in an older adult without other kidney problems is often normal. Sudden drops are more meaningful than gradual, stable readings.
- Lower than the usual range
- Reduced kidney function, dehydration or certain medications.
- Within the usual range
- A result inside the range printed by the laboratory is generally read as usual for eGFR at the time of the test.
- Higher than the usual range
- A higher result is a prompt to look further — clinicians read it alongside your symptoms, medicines and other tests.
Normal ranges are guides, not verdicts. Interpretation depends on your age, sex, symptoms, medical history, medications and other investigations — which is why your clinician looks at the whole picture rather than a single value.
Common reasons it may be low
Reduced kidney function
Damage to the filtering units of the kidney lowers eGFR — sometimes reversible, sometimes long-term.
Dehydration
Reduces blood flow through the kidneys and drops eGFR temporarily.
Some medications
Anti-inflammatories and certain other drugs can reduce eGFR while being taken.
Recent illness
Infections and severe illness can temporarily impair kidney filtration.
Older age
eGFR naturally decreases slowly over the decades.
Does an abnormal result always mean something is wrong?
Not necessarily. A number that sits outside the printed range is a prompt for interpretation — not a diagnosis.
- A single result rarely gives the full picture — clinicians interpret it alongside your symptoms.
- Your medical history, medications and other blood tests all shape the meaning of one value.
- Small movements just outside the reference range are common and often not concerning.
- Repeat testing over time is frequently more useful than any single number.
What might happen next?
- A repeat eGFR after a few weeks to confirm the trend.
- Urine tests looking for protein or blood.
- Blood-pressure and blood-sugar checks.
- Referral to a kidney specialist if the result is significantly reduced or falling.
One result rarely tells the whole story. Clinicians look at your symptoms, medical history, medications and other tests together — and a single value that sits slightly outside the reference range is often normal for you. Repeat testing over time is frequently more useful than any one number. Medipher helps you understand what a result means in plain English, but it cannot diagnose medical conditions or replace advice from a doctor, nurse or pharmacist.
When should I speak to a healthcare professional?
Speak with your GP or another healthcare professional if:
- You've been asked to repeat the test.
- You're experiencing new or worsening symptoms.
- Your clinician has flagged the result as needing follow-up.
- You don't understand your results or feel unsure what to do next.
If you have severe symptoms — chest pain, severe breathlessness, fainting, heavy bleeding or feel very unwell — seek urgent help. If this is a medical emergency, call your local emergency number immediately. Medipher is designed to help explain medical information and is not an emergency service.
Frequently asked questions
Related guides
Commonly confused with
These tests sound similar to eGFR, but each answers a different question.
- CreatinineCreatinine is the measured waste product; eGFR is a calculation based on it, plus age and sex.
- UreaUrea is another waste product, and it moves with hydration and diet more readily than eGFR does.
- Kidney function testsThat is the whole panel — eGFR is one number within it, read alongside creatinine, urea and electrolytes.
Learning collections
Follow a guided pathway that puts eGFR in context, step by step.
Still unsure what your result means?
This page explains one medical term. If you have a blood test, GP letter or hospital report, Medipher can explain your entire document in plain English.
- what your results mean
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Sources
General patient information referenced when writing this page.
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About this page
- Author
- Omer Suliman
- Medical reviewer
- Clinical review pending
Evidence. Written from public patient-information sources including the NHS, NICE and the Association for Laboratory Medicine, and reviewed for plain-English accuracy before publication.
Educational content only. Medipher explains medical language in plain English. It does not diagnose, and it is not a substitute for advice from a doctor, nurse or pharmacist. Read the medical disclaimer.
Nearly there — keep going.
A short summary and recommended next reads are just below.
Continue learning
- Next upCreatinineA waste product from normal muscle activity that the kidneys filter out of your blood.
- Next upUreaA waste product formed when your body breaks down protein. The kidneys filter it out of your blood.
- Next upAbnormal (on a test report)A flag meaning a result differs from what the laboratory or test expected — not a statement about your health.
This glossary entry is general health information, not medical advice. Medipher explains medical wording in plain English and does not diagnose, provide treatment advice, or replace a GP, doctor, nurse or pharmacist. Always discuss your results with a qualified clinician.