What does a low eGFR mean?

A low eGFR means the kidneys are filtering less blood than expected. A value under 60 mL/min/1.73m² sustained for at least three months indicates chronic kidney disease, staged from G3a to G5 by how low it is.

What causes a low eGFR?

Common causes include diabetes, high blood pressure, and other chronic kidney conditions, as well as ageing and temporary factors like dehydration. A single low reading may not be permanent, so it is repeated and interpreted in context.

Low eGFR: Causes & Meaning

What reduced filtration means and what raises it.

Medically reviewed by Dr. Rishi Kumar Kafle, MBBS, MD, FASN · Last reviewed June 2026

A low eGFR means the kidneys are filtering less than expected. A value under 60 mL/min/1.73m² that lasts three months or more indicates chronic kidney disease.

Common Causes

A low eGFR has many possible causes, and they fall broadly into lasting kidney conditions, normal ageing, and temporary factors that may reverse. The two leading drivers of chronic kidney disease are diabetes and high blood pressure, which damage the small filtering vessels in the kidneys over years. Knowing which group a low reading falls into is what shapes whether it is likely to recover or to need ongoing management.

Diabetes and high blood pressure, the leading causes of chronic kidney disease.
Other kidney conditions, such as glomerular disease or polycystic kidney disease.
Normal ageing, which lowers eGFR gradually — see eGFR by age.
Temporary factors such as dehydration or reduced blood flow, which may reverse.
Some medicines, which can affect creatinine or kidney blood flow and are reviewed by your clinician.

How Low eGFR Is Staged

Below 60, eGFR is divided into CKD stages: G3a (45–59), G3b (30–44), G4 (15–29), and G5 (under 15). Many people in the early stages have stable kidney function for years. See the full CKD stages.

Low eGFR by stage (mL/min/1.73m²)
eGFR	Stage	What it means
45–59	G3a	Mild to moderate reduction — often stable
30–44	G3b	Moderate to severe reduction
15–29	G4	Severely reduced — planning for later care begins
< 15	G5	Kidney failure — symptoms and treatment options discussed

A lower number sits further down this scale, but the stage is only one part of how risk is judged. Albuminuria and the trend over time matter just as much, which is why two people at the same eGFR can have very different outlooks.

Why One Low Reading Is Not a Diagnosis

Filtration can drop briefly for reasons that have nothing to do with lasting kidney disease — being dehydrated, recovering from an illness, or starting a new medicine can all push a single result down. Because of this, a low eGFR is treated as a prompt to repeat the test, not as a final answer. Chronic kidney disease is only defined when the value stays under 60 for three months or more. A first low reading that returns to normal on a repeat test usually reflects a temporary cause rather than a permanent change.

How the Number Is Read in Context

A clinician interprets a low eGFR using more than the figure itself. The most important companions are:

Albuminuria — a urine albumin-to-creatinine ratio that shows whether protein is leaking into the urine. Heavy albuminuria raises risk at any eGFR.
The trend — a stable value over years is far more reassuring than one that is falling steadily.
Age — filtration declines with age, so a modestly low value in an older adult can be normal ageing. See eGFR by age.
Other tests — creatinine, blood pressure, and imaging round out the picture.

Putting the eGFR and the albuminuria together is what the KDIGO risk heat map does — it grades risk by combining how low filtration is with how much albumin is present, rather than using either measure alone.

What a Specific eGFR Means

Symptoms and When They Appear

Many people with a mildly or moderately low eGFR feel completely well and have no symptoms at all — the change is found on a routine blood test. Symptoms, when they appear, tend to come only at much lower filtration levels and can include tiredness, swelling in the legs or around the eyes, changes in how much you pass urine, or poor appetite. Because these are non-specific and can have many causes, they are not used to judge eGFR on their own. The absence of symptoms does not rule out a low eGFR, which is exactly why the blood test matters.

Can a Low eGFR Improve?

It depends on the cause. When a low reading is driven by a temporary factor — dehydration, a recent illness, or a new medicine — the eGFR often recovers once that factor resolves, which is why a repeat test is the usual next step. When the reduction reflects lasting kidney damage, the aim shifts from reversing it to protecting the filtration that remains and slowing any decline. Managing blood pressure, blood sugar, and albuminuria, and reviewing medications, are the mainstays. Many people with early-stage CKD keep stable kidney function for years with this kind of management.

What Comes Next

Because a single reading can be affected by short-term factors, a low eGFR is usually repeated and read alongside creatinine, urine tests, and your history. If it is confirmed below 60 over three months, it places you on the CKD staging scale, and your clinician will use the trend and your albuminuria to judge risk and plan monitoring. Estimate yours with the eGFR calculator, compare it with the normal range for your age, and bring any unexpected result to your doctor rather than acting on one figure alone.