eGFR (estimated glomerular filtration rate) estimates how much blood your kidneys filter each minute. A healthy young adult is usually above 90 mL/min/1.73m². An eGFR below 60 that lasts three months or more meets the definition of chronic kidney disease (CKD) stage 3. A single low result, or one between 60 and 89 with no other signs of kidney damage, is not a diagnosis on its own.
| Category | Reference range |
|---|---|
| G1: normal or high | 90 or more mL/min/1.73m² |
| G2: mildly decreased | 60–89 mL/min/1.73m² |
| G3a: mild to moderate | 45–59 mL/min/1.73m² |
| G3b: moderate to severe | 30–44 mL/min/1.73m² |
| G4: severe | 15–29 mL/min/1.73m² |
| G5: kidney failure | below 15 mL/min/1.73m² |
KDIGO stages. Stages G1 and G2 count as CKD only with other signs of kidney damage, such as protein in the urine. Many labs report any value above 90 simply as ">90".
eGFR is calculated from your creatinine level, age and sex using a formula (in the UK and US now usually CKD-EPI, without a race adjustment). It is an estimate, not a direct measurement, and it is less accurate at the extremes of body size and muscle mass.
Kidney function declines gradually with age, by roughly 1 mL/min a year after about 40, so an eGFR in the 60s or 70s is common in older adults. What doctors look for is a value below 60 that persists, a fast decline, or protein in the urine.
Your report may also show "eGFR (CKD-EPI)" or "eGFR creatinine"; some labs add an eGFR based on cystatin C, which is less affected by muscle mass. When both are available and differ, doctors often use the combined value. For people with very low or very high muscle mass, such as frail older adults, amputees or bodybuilders, cystatin C can give a more realistic estimate.
Doctors classify CKD by two numbers: the eGFR stage (G) and the amount of albumin in the urine, measured as the albumin-to-creatinine ratio (ACR) stage (A). A1 is under 3 mg/mmol (under 30 mg/g), A2 is 3 to 30 mg/mmol, and A3 above 30. An eGFR of 55 with a normal ACR carries a much lower risk than the same eGFR with a high ACR.
So if your eGFR is low, expect a request for a urine sample, ideally first thing in the morning.
A low eGFR should be reviewed by your GP or doctor, usually with a repeat test within two weeks to three months and a urine ACR. Get urgent help (NHS 111, urgent care, A&E or the emergency room) if:
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No need to decode the numbers yourself: take a photo of the report and the app explains “Low eGFR” and the rest in plain words — what is normal and what deserves attention.
App StoreGoogle PlayWeb versionIt is mildly reduced (the border between stage G2 and G3a). Without protein in the urine or other kidney problems, it does not count as kidney disease, and it is common in older adults.
Stage G3a, if it stays below 60 for at least three months. A single result of 55 needs repeating before any diagnosis.
Yes, when the drop was caused by dehydration, a medicine or an acute illness. In chronic kidney disease the aim is usually to slow any further decline, which is often possible.
Because eGFR also uses age and sex. An older person can have a normal-looking creatinine but an eGFR below 60. Your doctor will weigh both, plus urine tests.
Usually not until kidney function is quite reduced. Early stages are found almost only through blood and urine tests.
If you were dehydrated when the sample was taken, rehydrating can bring eGFR back up. Drinking large amounts beyond normal needs does not improve kidney function further.
This material is for general information only. It is not a medical opinion and does not replace a consultation with a doctor. Reference ranges depend on the laboratory and the method — rely on the range printed on your own report. Your doctor makes the final interpretation.
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