What does eGFR mean?

eGFR stands for estimated glomerular filtration rate. It is an estimate of how well your kidneys are filtering the blood. Most laboratories calculate it automatically from your creatinine, age and sex, and report it alongside your kidney blood tests.

How should I read the number?

In general, a higher eGFR means better filtering function. An eGFR of 90 or more can be normal, while persistent values below 60 may indicate chronic kidney disease. Values below 30 suggest more advanced kidney impairment, and values below 15 may be seen in kidney failure. However, these ranges do not tell the full story by themselves.

Does one low eGFR mean I have chronic kidney disease?

Not necessarily. Chronic kidney disease means that an abnormality has been present for at least three months, or that there is other evidence of kidney damage such as persistent protein in the urine or an abnormal kidney structure. eGFR may temporarily fall during dehydration, infection, medication changes or acute illness.

Why can eGFR be confusing?

It is an estimate rather than a direct measurement. It is less precise at very high levels of kidney function and can be affected by unusual muscle mass, major changes in diet or body composition, and certain illnesses. For this reason, doctors interpret eGFR together with urine tests, symptoms and the trend over time.

What should I pay attention to?

Look at the direction of travel. A stable eGFR of 45 over several years is different from an eGFR that has fallen from 80 to 45 over a few months. The speed of change often matters as much as the stage itself.