Low eGFR
eGFR estimates how much blood your kidneys filter each minute. It’s worked out from creatinine, a waste product from muscle, plus your age and sex. A single low result is often a temporary dip, so it’s always worth a repeat.
Quick answer: An eGFR over 90 is normal and 60–89 is often normal for age. Under 60 for at least 3 months, or albumin in the urine, means chronic kidney disease. One-off dips are common with dehydration, illness, a big meat meal or creatine. Retest within a week. Under 30 needs a kidney specialist.
What the test measures
Healthy kidneys filter waste such as creatinine out of the blood. When filtering slows, creatinine builds up and the calculated eGFR falls. Australian labs report it in mL/min/1.73 m² and usually show anything above 90 simply as “>90”. Want to see how it’s calculated? Try our eGFR calculator.
Kidney stages (KDIGO)
- G1, 90 or more: normal (kidney disease only if there are other signs of damage, such as albumin in urine)
- G2, 60–89: mildly reduced, and normal for many older adults
- G3a, 45–59: mildly to moderately reduced
- G3b, 30–44: moderately to severely reduced
- G4, 15–29: severely reduced
- G5, under 15: kidney failure
Chronic kidney disease (CKD) means an eGFR under 60, or signs of kidney damage, for at least 3 months. eGFR falls slowly with age. It isn’t reliable in pregnancy, children, people on dialysis or at extremes of body size.
What a low result usually means
Temporary or misleading causes (why a repeat matters):
- Dehydration or a recent illness, especially vomiting and diarrhoea.
- A meal of cooked meat in the hours before the test.
- Creatine supplements, a very high-protein diet or a lot of muscle.
- Medicines that raise creatinine without harming the kidney, such as trimethoprim and fenofibrate. Blood pressure medicines (ACE inhibitors and ARBs) and SGLT2 inhibitors often cause a small, expected dip when started.
Common long-term causes:
- Diabetes and high blood pressure, the two biggest causes of CKD.
- Ageing kidneys, heart disease and smoking.
- Regular use of anti-inflammatories such as ibuprofen.
Less common but important:
- Acute kidney injury: a sudden drop from dehydration, infection, blockage or medicines.
- Glomerulonephritis (inflammation of the kidney filters), often with blood or protein in the urine.
- Blockage, for example from an enlarged prostate or kidney stones; polycystic kidney disease and other inherited conditions.
Symptoms
Usually none until kidney function is quite low, which is why testing matters. Later symptoms include tiredness, swollen ankles, itch, poor appetite, nausea and getting up at night to pass urine.
What happens next
- Repeat the test within 7 days if this is a new result under 60, to check for a sudden change. Avoid cooked meat for several hours beforehand.
- Urine albumin-to-creatinine ratio (ACR): protein in the urine is as important as eGFR for predicting risk.
- Blood pressure, blood sugar, cholesterol and a urine test for blood.
- A medicine review: avoid anti-inflammatories, and some doses may need adjusting.
- Treatment focuses on protecting the kidneys: blood pressure control, an ACE inhibitor or ARB if there’s albumin in the urine, and often an SGLT2 inhibitor.
- Kidney specialist referral (Kidney Health Australia) for an eGFR under 30, an ACR of 30 mg/mmol or more, a sustained fall of 25% or more within 12 months (or 15 mL/min/1.73 m² in a year), or blood pressure above target despite three medicines.
See a doctor the same day if your eGFR has dropped sharply from your usual level, especially if you’re passing much less urine, vomiting or feeling very unwell, or if you have blood in your urine with swelling and high blood pressure. Get urgent help (000 in Australia, or your local emergency number) for confusion, severe breathlessness or chest pain. An eGFR under 15 needs prompt specialist care.
Practise reading results. Play Panelysis, the daily blood-test puzzle: a fictional patient, a real-looking panel, three guesses. More in medical games.
Common questions
Is an eGFR of 55 bad?
It’s stage G3a, mildly to moderately reduced. If it stays there for 3 months it counts as chronic kidney disease, but most people at this level never need dialysis, especially without protein in the urine. The key steps are a repeat test, a urine ACR, and good blood pressure and diabetes control.
Can my eGFR go back up?
Yes, if the low result was a temporary dip from dehydration, illness, a meat meal or a medicine. Loss from long-term kidney disease usually doesn’t recover, but treatment can slow or stop further decline.
Will drinking more water improve my eGFR?
Only if you were dehydrated. Rehydrating can bring a dipped result back to your usual level, but drinking extra water beyond your normal needs won’t improve kidney function.
What eGFR level needs dialysis?
Dialysis or a transplant is usually considered when eGFR falls below 15 with symptoms of kidney failure, though the decision depends on how you feel, not just the number. Many people with low eGFR are managed for years without dialysis.
Does eGFR go down with age?
Yes. Kidney filtering slowly declines with age, so an eGFR of 60–89 is common and often normal in older adults if there are no other signs of kidney damage.
Can creatine supplements or protein shakes affect eGFR?
Yes. Creatine supplements, a very high-protein diet and big muscles all raise creatinine, which makes eGFR look lower than your real kidney function. Tell your doctor if you use them; a cystatin C test can help.
Evidence and more information
- Pathology Tests Explained (RCPA): eGFR
- Kidney Health Australia: CKD Management in Primary Care handbook (retesting, referral criteria)
- KDIGO 2024 clinical practice guideline for the evaluation and management of CKD
- Kidney Health Australia: Stages of kidney disease
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