eGFR

Also written as: Estimated glomerular filtration rate

A calculated estimate of how well your kidneys are filtering.

What it measures

Not a measured value but a calculation. A formula combines your creatinine with your age and sex to estimate how much blood your kidneys filter per minute.

Why a doctor orders it

It is reported automatically alongside creatinine because the calculated number is easier to track over time than creatinine alone, and it is the basis for staging chronic kidney disease.

What is generally associated with a higher result

A higher eGFR indicates more filtering capacity and is generally the desirable direction.

What is generally associated with a lower result

A lower eGFR indicates reduced filtering. Broadly associated with chronic kidney disease, acute kidney injury, dehydration, and the gradual decline that occurs with age.

Everyday things that move this number

Not every shift in a value reflects disease. These are ordinary factors known to affect this particular measurement:

Everything that affects creatinine, since it is calculated from it
The specific formula your lab uses, which has changed over the years
Being a single point in time rather than a trend

Questions to take to your appointment

Is this a change from my previous results or a stable number?
Should this be rechecked when I am well hydrated?

Build a printable questionnaire with your own results →

Where to read more

MedlinePlus, from the US National Library of Medicine, publishes patient-facing pages on individual lab tests and is a reliable next stop: medlineplus.gov/lab-tests .

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