Kidney health · 6 min read
Understanding your eGFR — CKD stages G1 to G5.
Got an eGFR result and a stage like "G3a" and not sure what it means? This explains the KDIGO staging system in plain English — what each stage signifies, why albuminuria is part of the picture, and why one reading is never the whole story.
Last updated April 15, 2026.
The CKD stages by eGFR
Chronic kidney disease is staged by eGFR into six bands. Higher numbers are better. A key nuance: stages G1 and G2 are only considered chronic kidney disease when there's also evidence of kidney damage — most often albuminuria — because a normal eGFR with no other findings simply means healthy kidneys.
| Stage | eGFR | Meaning |
|---|---|---|
| G1 | ≥ 90 | Normal or high (CKD only if kidney damage present) |
| G2 | 60 – 89 | Mildly decreased (CKD only if kidney damage present) |
| G3a | 45 – 59 | Mildly to moderately decreased |
| G3b | 30 – 44 | Moderately to severely decreased |
| G4 | 15 – 29 | Severely decreased |
| G5 | < 15 | Kidney failure |
Why albuminuria is part of the staging
Modern CKD staging (the KDIGO system) uses two axes, not one: eGFRand albuminuria. Albumin in the urine is an early signal of kidney damage and independently predicts how the disease will progress. It's graded in three categories:
- A1 — normal to mildly increased (under 30 mg/g).
- A2 — moderately increased (30–300 mg/g).
- A3 — severely increased (over 300 mg/g).
Two people can share the same eGFR but face very different risk depending on their albuminuria. That's why your doctor looks at both.
Why one reading isn't a diagnosis
A diagnosis of chronic kidney disease requires the abnormality — eGFR under 60, or markers of damage — to persist for at least three months. eGFR can drop transiently from dehydration, NSAIDs, ACE inhibitors, or an acute illness and then recover. So a single low value is a prompt to recheck, not a conclusion.
What each stage means for care
- G1–G2: usually managed in primary care; focus on the cause and on protecting kidneys (blood pressure, blood sugar, avoiding NSAIDs).
- G3a–G3b: closer monitoring, sometimes a nephrology referral, attention to medication doses and complications.
- G4: nephrology care and planning ahead for kidney replacement therapy.
- G5: kidney failure — dialysis or transplant, guided by symptoms and individual factors.
Frequently asked questions
What do the CKD stages G1 to G5 mean?+
They describe kidney function by eGFR: G1 is ≥90 (normal), G2 is 60–89 (mildly decreased), G3a is 45–59, G3b is 30–44 (moderately decreased), G4 is 15–29 (severely decreased), and G5 is below 15 (kidney failure). G1 and G2 are only classified as chronic kidney disease if there is also evidence of kidney damage, such as albuminuria.
Does one low eGFR mean I have chronic kidney disease?+
No. Chronic kidney disease requires an eGFR below 60, or markers of kidney damage, persisting for at least three months. A single low reading should be repeated, because eGFR can fall temporarily from dehydration, medications, or acute illness.
What is albuminuria and why does it matter?+
Albuminuria is protein (albumin) leaking into the urine, an early sign of kidney damage. KDIGO grades it A1 (normal, under 30 mg/g), A2 (moderately increased, 30–300 mg/g), and A3 (severely increased, over 300 mg/g). Staging uses both eGFR and albuminuria together because albuminuria independently predicts risk.
What eGFR level requires dialysis?+
Dialysis or transplant is generally considered in stage G5 (eGFR below 15), guided by symptoms and individual factors rather than the number alone. Earlier stages are managed to slow progression, not with dialysis.
Estimate your eGFR and see your KDIGO stage with the CKD-EPI 2021 calculator.
For general education only. Not medical advice or a diagnosis. Discuss your results with a qualified healthcare professional. Reference: KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int. 2024.