What this marker measures
Kidney function naturally declines slightly with age. A single low eGFR reading is less informative than a trend over time. Chronic kidney disease (CKD) is defined by persistently reduced eGFR and/or markers of kidney damage.
High or low: what it can mean
High eGFR
eGFR values above 90 are generally considered normal. A very high calculated eGFR (e.g. > 120) may simply reflect young age, high muscle mass, or test variability rather than "better" kidney function.
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Low eGFR
A lower eGFR means the kidneys are filtering less blood per minute than expected. Values between 60–89 may warrant monitoring; values below 60 on repeated testing indicate reduced kidney function and are usually investigated further.
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Lifestyle considerations
- •Blood pressure control, avoiding NSAIDs long-term, and staying hydrated are key for kidney health
Frequently asked questions
What is eGFR?
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eGFR estimates how many millilitres of blood the kidneys filter per minute. It is calculated from serum creatinine, age, sex, and sometimes race, providing a standardised measure of kidney function.
What does eGFR measure?
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Kidney function naturally declines slightly with age. A single low eGFR reading is less informative than a trend over time. Chronic kidney disease (CKD) is defined by persistently reduced eGFR and/or markers of kidney damage.
What does high eGFR mean?
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eGFR values above 90 are generally considered normal. A very high calculated eGFR (e.g. > 120) may simply reflect young age, high muscle mass, or test variability rather than "better" kidney function.
What does low eGFR mean?
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A lower eGFR means the kidneys are filtering less blood per minute than expected. Values between 60–89 may warrant monitoring; values below 60 on repeated testing indicate reduced kidney function and are usually investigated further.
What supports healthy eGFR levels?
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Blood pressure control, avoiding NSAIDs long-term, and staying hydrated are key for kidney health
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.