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Kidney

The eGFR on your result: calmly explained

Your eGFR value tells you how many millilitres of blood your kidneys clean per minute, and one number under 60 says far less than it seems. eGFR stands for estimated glomerular filtration rate, and that word estimated is the important one: nobody measured your kidneys. The lab took your creatinine, a waste product of your muscles that your kidneys remove from your blood, plus your age and your sex, and calculated a number from them. Above 90 is normal, 60 to 89 is called mildly reduced, and the latter is the rule rather than the exception at older ages. Chronic kidney damage only exists once the value stays under 60 for at least three months. That is why your doctor repeats the test, and that is correct procedure and not delay.

Doctor's Assessment Included

When is this value abnormal?

Decision limits per result, in ml/min/1,73m²
Result Value (ml/min/1,73m²)
G5 – kidney failure < 15
G4 – severely decreased 15–30
G3b – moderately to severely decreased 30–45
G3a – mildly to moderately decreased 45–60
G2 – mildly decreased 60–90
G1 – normal or high ≥ 90

The eGFR is not judged against a single normal value, but with the stages G1 to G5 from the Dutch guideline on chronic kidney disease (NHG/NIV, based on KDIGO). The value is an estimate: it is calculated with the CKD-EPI formula from the creatinine in your blood, your age and your sex. The stage alone does not say whether there is kidney damage: for that the doctor also looks at the albumin-creatinine ratio (ACR) in the urine, and at whether an abnormality persists for at least 3 months. Even at stage G1-G2 there can be kidney damage if albuminuria is raised; with normal albuminuria, G1-G2 counts as no chronic kidney disease (together about 88% of the population). An eGFR below 60 that lasts longer than 3 months is called chronic kidney disease, and the GP adjusts medication doses where needed. Discuss your result with your GP.

Source: NHG Reference population: All adults (KDIGO/NHG staging, independent of age)

Reference ranges may vary between laboratories. When you order a test, a BIG-registered doctor assesses your personal results in context. For treatment decisions, discuss your results with your GP.

eGFR (Estimated Glomerular Filtration Rate): what this test measures

The e in eGFR stands for estimated, and that small word matters more than it looks. Nobody actually measured your filtration. The lab took your creatinine, your age and your sex, put those three into an equation, and a number came out: the number of millilitres of blood your kidneys would filter per minute if you had an average build.

That equation is called CKD-EPI. Some labs also report an EKFC result; those are two ways of calculating the same question and they can differ by a few points. Since 2021 neither uses a race coefficient any more.

An estimate is not a bad measurement. For most people it is more than good enough. But it does explain why the number moves between two draws: anything that raises your creatinine temporarily, such as a big meat meal or a hard workout, pushes the calculated value down without your kidneys having changed.

eGFR (Estimated Glomerular Filtration Rate): why this value matters

The number most people find alarming sits just under 60. Yet one such result is not a diagnosis. Chronic kidney damage needs the value to stay low for at least three months, or protein to be present in your urine. That is why your doctor repeats the test, and that is not delay but correct procedure.

Above 90 is normal. Between 60 and 89 is called mildly reduced, and in older people that is the rule rather than the exception, because the value falls on its own by about 1 ml/min per year from age forty. A seventy-year-old with a value of 75 is simply fine. Between 45 and 59 your doctor looks at the trend and at your urine, and below 30 a kidney specialist comes into the picture.

More important than one number is the trend across several years. A stable 75 is more reassuring than an 85 that falls every year. So compare your results with one another, and with the conditions under which you gave blood.

Higher is not automatically better. Above 90 many labs stop giving an exact number, because the equation becomes imprecise there, and very high values sometimes accompany early diabetes. And a normal eGFR does not prove your kidneys are healthy: protein in your urine can show damage while your filtration is still ordinary. That is why your doctor often requests both.

eGFR (Estimated Glomerular Filtration Rate): how the blood test works

Referral
No GP referral needed. After the order we arrange the referral through ZorgDomein, within one business day; orders after 17:00 or at the weekend start on the next business day. ZorgDomein emails a barcode, and that barcode is what the draw site needs.
The draw
A blood draw from a vein in the arm, at a partner laboratory's draw site. No home kit, no finger prick.
Which test
on its own €7,- Kidney Function · €69,- · Extended Health Checkup · €259,- · Complete Metabolic Panel · €149,- · Whoop · €499,-
Where
650+ draw sites run by independent laboratories across the Netherlands. Draw sites

eGFR (Estimated Glomerular Filtration Rate): when is testing worthwhile?

Usually you need to arrange nothing for this. The eGFR comes along automatically as soon as creatinine is measured, and that happens in almost every standard blood test. With diabetes, high blood pressure or kidney disease in the family the number carries more weight.

Five everyday things can lower the number temporarily: a big meat meal shortly before the draw, a hard workout in the days before, drinking too little, creatine supplements, and the antibiotic trimethoprim. None of the five damages your kidney; they only raise the creatinine the calculation uses.

For the cleanest possible result, book the draw on an ordinary day, not after a party and not after the gym, and drink normally. If the value stays low your doctor looks further; often cystatin C, another substance from which filtration can be estimated, or a urine test follows.

eGFR (Estimated Glomerular Filtration Rate): symptoms of a high or low value

Low Levels

You do not feel a mildly lowered eGFR, and most people with a value between 60 and 89 notice nothing and have nothing. Symptoms belong to kidneys that genuinely and persistently filter less: feeling tired without a clear reason, swollen ankles or feet at the end of the day, blood pressure creeping upward, less appetite or a queasy feeling, feeling less sharp than usual, and foam on your urine that lingers. If you recognise any of that alongside a low value, see your GP instead of waiting for the next measurement.

High Levels

A high eGFR causes no symptoms. Above 90 your lab usually stops giving an exact number, because the equation becomes imprecise there, so "greater than 90" is simply a normal result. Very high values that persist sometimes accompany early diabetes or excess weight; the kidneys then filter under raised pressure, and that is called hyperfiltration. So higher is not automatically better, and a high eGFR does not prove your kidneys are healthy.

eGFR (Estimated Glomerular Filtration Rate): what to do about an abnormal value

Male

If Low

Low eGFR indicates reduced kidney function. Consult a nephrologist for evaluation and management.

If High

Normal to high eGFR indicates healthy kidney function. Maintain kidney-healthy habits.

Female

If Low

Low eGFR indicates reduced kidney function. Consult a nephrologist for evaluation and management.

If High

Normal to high eGFR indicates healthy kidney function. Maintain kidney-healthy habits.

eGFR (Estimated Glomerular Filtration Rate): lifestyle and this value

Your kidneys mostly like boring things. Normal blood pressure, stable blood sugar and drinking enough protect them better together than any supplement, and there is no supplement that improves filtration.

Go easy on over-the-counter painkillers, especially NSAIDs such as ibuprofen and naproxen. With prolonged use, and certainly if you drink little at the same time, they can strain the kidney. Paracetamol is the milder choice for the kidneys.

If you smoke, quitting helps your kidneys too, because smoking damages the blood vessels in the kidney.

If you take regular medication, talk it through with your GP once. Your doctor uses your eGFR to choose doses, so never change anything you take on your own.

eGFR (Estimated Glomerular Filtration Rate): frequently asked questions

What is a good eGFR value?

A value of 90 or above counts as normal. Between 60 and 89 is called mildly reduced, which is the rule rather than the exception at older ages. More important than one number is the trend across several years: a stable 75 is more reassuring than a falling 85. Higher, by the way, is not always better.

Is an eGFR of 58 serious?

On its own that is not a diagnosis. Chronic kidney damage needs the value to stay below 60 for at least three months, which is why your doctor repeats the test. Also check whether confounders were at play, such as a meat meal, hard exercise or drinking too little in the days before.

What does the e in eGFR mean?

The e stands for estimated. Nobody actually measured your filtration: the lab took your creatinine, your age and your sex and put them into an equation. That also explains why the number moves between two draws.

eGFR (Estimated Glomerular Filtration Rate): sources

  1. Nederlands Huisartsen Genootschap. NHG-Standaard Chronische nierschade (M109), april 2018, laatste aanpassing februari 2026. Tabel 1, stadiëring op basis van eGFR: G1 >= 90, G2 60-89, G3a 45-59, G3b 30-44, G4 15-29, G5 < 15 ml/min/1,73 m2. Corroboratie: Multidisciplinaire richtlijn Chronische nierschade (NIV/NHG 2018, stadiëring naar KDIGO) en KDIGO 2024 CKD guideline. Geraadpleegd 14 juli en 9 augustus 2026. (retrieved 2026) richtlijnen.nhg.org

Test Products

This marker is included in the following test panels.

Health Checkups

Complete Metabolic Panel

Comprehensive metabolic panel: electrolytes, kidney, liver, glucose, HbA1c, and protein.

Bicarbonate Calcium Chloride Potassium Sodium Glucose (Fasting) HbA1c (Glycated Hemoglobin) Albumin ALP (Alkaline Phosphatase) ALT (Alanine Aminotransferase) AST (Aspartate Aminotransferase) Bilirubin (Total) Urea (BUN) Creatinine eGFR (Estimated Glomerular Filtration Rate) Total Protein Bilirubin (Direct) Bilirubin (Indirect)
€149,-
Whoop

Whoop

A 45-biomarker comprehensive health panel inspired by WHOOP Advanced Labs — a deep look at metabolism, cardiovascular risk, hormones, liver, kidney and inflammation.

SHBG (Sex Hormone Binding Globulin) TSH (Thyroid Stimulating Hormone) ALT (Alanine Aminotransferase) LDL Cholesterol Cortisol DHEA-S Estradiol (E2) Free Testosterone FSH (Follicle Stimulating Hormone) LH (Luteinizing Hormone) Total Testosterone Bicarbonate Calcium Chloride Ferritin Iron (Serum) Magnesium Potassium Sodium Transferrin CRP (C-Reactive Protein) Homocysteine Glucose (Fasting) HbA1c (Glycated Hemoglobin) ApoB (Apolipoprotein B) HDL Cholesterol Total Cholesterol Albumin HOMA-IR ALP (Alkaline Phosphatase) AST (Aspartate Aminotransferase) Bilirubin (Total) Total Protein Urea (BUN) Creatinine Vitamin D (25-OH) eGFR (Estimated Glomerular Filtration Rate) Insulin (Fasting) Leukocyte Differential Transferrin Saturation Lipoprotein(a) Triglycerides Basic Blood Count Bilirubin (Direct) Bilirubin (Indirect) Cholesterol/HDL Ratio Non-HDL Cholesterol LDL/HDL Ratio
€499,-

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Medical policy
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eGFR (Estimated Glomerular Filtration Rate)

€7,-