eGFR Stages: Why CKD Takes 3 Months to Confirm

Your eGFR places you in one of five kidney disease stages: G1 is 90 or higher, G2 is 60–89, G3a is 45–59, G3b is 30–44, G4 is 15–29, and G5 is below 15 mL/min/1.73 m². A CKD diagnosis also needs an eGFR under 60 or kidney damage, such as a urine albumin-to-creatinine ratio (uACR) of 30 mg/g or more, lasting three months or longer.

TL;DR:

• A single low result does not confirm CKD: dehydration, illness, or medication effects can shift eGFR, so clinicians repeat testing to rule out temporary causes.
• When eGFR is near a stage cutoff, clinicians may add cystatin C; the combined creatinine and cystatin C equation is more accurate at decision points.
• Two people with the same eGFR can face different risks because uACR also predicts progression; higher albuminuria or falling eGFR prompts closer monitoring.
• The standardized eGFR is used for CKD staging, while the body surface area adjusted value in mL/min guides medication dosing; the values can differ.
• At eGFR below 15, clinicians plan for dialysis or transplant, but timing depends on symptoms and overall health, not the number alone.

Table of Contents

• Which eGFR number matches which CKD stage?
• How do doctors confirm chronic kidney disease?
• How is eGFR estimated, and what can throw it off?
• What do eGFR stages mean for monitoring, referral, and dialysis planning?
• Reading eGFR results with calm and a plan
• How we can help if your eGFR is low
• FAQ
• Sources

Which eGFR number matches which CKD stage?

Chronic kidney disease stages are labeled G1 through G5, and each one maps to a range of eGFR, which is a blood-test estimate of how well your kidneys filter. The ranges below come from the National Kidney Foundation’s best practices document, and the unit is mL/min/1.73 m².

Here is how to read each row:

• G1: Filtration is normal, so this counts as CKD only when other signs of kidney damage are present, such as protein in the urine.
• G2: Filtration is slightly lower, and the same rule applies: damage must be documented to call it CKD.
• G3a: This is the first stage where the number alone signals disease, usually with no symptoms you would notice.
• G3b: Kidney function is further down, and your care team will typically watch closely for complications.
• G4: Planning conversations about future treatment options often start here.
• G5: This is kidney failure, and treatment planning becomes the priority.

An eGFR above 60 with no other marker of kidney damage does not meet the criteria for CKD. That is why a result in the G1 or G2 range, for example, is usually not a diagnosis by itself. This is also the answer to the common question about what an eGFR of 60 means: it sits at the border between G2 and G3a, and one reading at that level calls for context and repeat testing rather than alarm.

How do doctors confirm chronic kidney disease?

One lab result is a snapshot, not a verdict. A single eGFR below 60 is not enough for a CKD diagnosis, because guidelines ask for confirmation that function or damage persists for at least three months.

The formal rule has three parts:

• Either an eGFR below 60 mL/min/1.73 m² or a marker of kidney damage, most commonly a uACR of 30 mg/g or higher
• The abnormality lasts three months or more
• Repeat testing rules out temporary causes of a low number

Repeat testing matters because eGFR can swing for short-term reasons such as dehydration, illness, or a new medication. Clinicians use repeat results over time to separate a passing dip from chronic disease.

The urine test adds a second dimension. Albuminuria is grouped into categories A1, A2, and A3, from normal to severely increased, and it is a powerful independent predictor of risk that often guides treatment more precisely than eGFR alone. Two people with the same eGFR can have very different outlooks depending on their uACR. You can learn more about reading that result in our post on microalbumin urine test results.

Pro Tip: Ask whether your eGFR or uACR abnormality has persisted for at least three months. That persistence helps determine whether it meets the criteria for CKD.

How is eGFR estimated, and what can throw it off?

eGFR is a calculation, not a direct measurement. Labs plug your serum creatinine, age, and sex into a formula. The current adult standard is the race-free 2021 CKD-EPI creatinine equation, and NIDDK notes that combined creatinine–cystatin C equations are more accurate, especially near critical decision values.

When your result sits close to a cutoff, your clinician may order cystatin C, a second blood marker that improves accuracy in borderline cases.

Several things unrelated to kidney disease can nudge your number:

• Hydration, since being dry can raise creatinine temporarily
• A recent high-protein meal or heavy meat intake
• Medications that affect creatinine or kidney blood flow
• Muscle mass, because very muscular or very frail people may be misjudged by creatinine
• Normal variation between labs and between draws

Supplements can play a role too. Creatine, popular with lifters, can raise creatinine without harming the kidneys, and a review of the evidence on creatine and kidneys explains why. Tell your provider what you take before a test.

Finally, there are two versions of eGFR. The standardized value (mL/min/1.73 m²) is used for staging. The BSA-adjusted value in mL/min is used for medication dosing, and the two can differ.

Key point: Labs should report which equation they used, and the NKF recommends that systems clearly label both eGFR values so staging and dosing do not get mixed up.

What do eGFR stages mean for monitoring, referral, and dialysis planning?

Your stage tells your care team how closely to follow you, but your uACR and other risk factors shape the plan just as much. Modern care is individualized and risk-based, and KDIGO’s 2024 guideline supports this approach. Risk factors for faster progression include diabetes with high albuminuria, high blood pressure, rising albuminuria, and falling eGFR.

Here is what that typically looks like in practice:

1. Monitoring frequency rises as risk rises. Lower eGFR or higher uACR means more frequent blood and urine checks, set by your clinician.
2. Medications get reviewed. Doses of some drugs change when filtration drops, which is where BSA-adjusted eGFR comes in.
3. Blood pressure and blood sugar targets tighten. These two are the biggest levers for slowing decline.
4. Newer therapies may be added. SGLT2 inhibitors are used to delay progression in appropriate patients, with or without diabetes.
5. Lifestyle measures matter. Eating patterns, physical activity, avoiding unnecessary anti-inflammatory painkillers, and not smoking all help. Our chronic disease management tips cover practical habits.
6. Referral and planning come later. Nephrology referral is generally considered as eGFR falls or albuminuria climbs, and an eGFR below 15 or established kidney failure means planning for dialysis or transplant.

Acute kidney injury is different from CKD. It is a sudden drop in kidney function, while CKD staging depends on abnormalities lasting three months or more.

Pro Tip: Keep a simple list of every eGFR and uACR result with its date. Seeing the trend helps your provider decide whether to watch, adjust, or refer.

Reading eGFR results with calm and a plan

One abnormal eGFR is common, and it is usually handled with repeat testing and simple next steps rather than anything dramatic. At our practice we typically order serum creatinine with eGFR and a uACR, and sometimes cystatin C if your number sits near a cutoff. A follow-up visit covers your results, medications, blood pressure, and a monitoring schedule. Bring your lab reports to your primary care provider so we can interpret them together.

— Garden State Medical Group

How we can help if your eGFR is low

If your eGFR or uACR is outside the range you expected, the next step is a conversation with a clinician who can look at the whole picture. We offer:

• Primary care visits, in person or by telemedicine, to review results and order confirmatory testing
• Chronic care management for ongoing monitoring and support
• On-site blood tests and coordination of diagnostic testing and specialist referrals

Schedule an appointment with us to go over your eGFR and uACR and set a monitoring or treatment plan that fits you.

This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.

FAQ

What is a good eGFR for my age?

An eGFR of 90 or higher is considered normal, and 60–89 is mildly reduced. Kidney filtration naturally declines with age, so a mildly reduced number without protein in the urine does not meet CKD criteria by itself.

Can drinking more water improve GFR?

Dehydration can temporarily lower eGFR, so being well hydrated before a test helps avoid a falsely low result. Extra water will not repair kidney damage, and clinicians repeat tests to separate temporary changes from chronic disease.

At what eGFR level do you start dialysis?

Kidney failure is defined as an eGFR below 15 mL/min/1.73 m², the G5 stage. Planning for dialysis or transplant starts around that point, but the decision also depends on symptoms and your overall health.

Can your eGFR go back to normal?

It can when the cause is temporary, such as dehydration, illness, or a medication effect. When the cause is chronic damage, the goal is usually to slow decline through blood pressure and blood sugar control and other risk-based care.

Recommended

• Under 30 mg/g? Microalbumin Urine Test Results and Where to Get Tested
• 7 Common Signs of Kidney Disease You Should Look Out For
• Blood Tests
• Hypertension Stages: What Your Numbers Mean and Next Steps