CKD Stages by eGFR: G1 to G5
The five GFR categories that define chronic kidney disease.
Medically reviewed by Dr. Rishi Kumar Kafle, MBBS, MD, FASN · Last reviewed June 2026
CKD is staged by eGFR into five GFR categories, G1 to G5. Stage G3 is split into G3a and G3b. A value below 60 sustained for three months indicates chronic kidney disease.
The CKD Stages
| Stage | eGFR range | Meaning |
|---|---|---|
| Stage 1 (G1) | ≥ 90 | Normal or high — with signs of kidney damage |
| Stage 2 (G2) | 60–89 | Mildly decreased |
| Stage 3a (G3a) | 45–59 | Mild to moderately decreased |
| Stage 3b (G3b) | 30–44 | Moderately to severely decreased |
| Stage 4 (G4) | 15–29 | Severely decreased |
| Stage 5 (G5) | < 15 | Kidney failure |
How Staging Works
Stages G1 and G2 are only called CKD when there is other evidence of kidney damage, such as albuminuria. From G3 onward, the reduced eGFR alone meets the definition. Full classification pairs the GFR category with an albuminuria category — see the KDIGO heat map. Staging also requires the eGFR to be sustained for at least three months, which separates lasting disease from a short-term dip caused by dehydration, illness, or a new medicine. A first result in a CKD range therefore usually leads to a repeat test rather than an immediate diagnosis, and the stage is only confirmed once the value is shown to persist.
What Each Stage Means
Reading the table from top to bottom, the stages describe a gradual loss of filtration, from normal function with signs of damage at the top to kidney failure at the bottom:
- Stage 1 (G1), eGFR ≥ 90 — filtration is normal or high, but a kidney-damage marker such as albuminuria is present. Read more on stage 1.
- Stage 2 (G2), eGFR 60–89 — mildly decreased filtration alongside signs of damage. See stage 2.
- Stage 3 (G3a 45–59, G3b 30–44) — the most common stage, where reduced eGFR alone meets the definition. See stage 3.
- Stage 4 (G4), eGFR 15–29 — severely decreased; planning for later treatment options usually begins. See stage 4.
- Stage 5 (G5), eGFR < 15 — kidney failure, where dialysis or transplant is discussed based on symptoms. See stage 5.
Why eGFR, Not a Single Creatinine
Staging uses eGFR rather than a raw creatinine value because creatinine varies with muscle mass, age, and sex. The same creatinine can reflect very different kidney function in a young athlete and an older, smaller adult. eGFR adjusts for these factors and standardises the result to an average-sized body, so it places everyone on the same scale. This is also why kidney failure is defined as an eGFR below 15, not by a fixed creatinine number.
Why Stage 3 Is Split Into G3a and G3b
Stage 3 covers a wide span of filtration, from an eGFR of 30 up to 59, so it is divided into two parts. G3a (45–59) is a mild-to-moderate reduction, while G3b (30–44) is moderate-to-severe. Splitting the stage matters because risk and management differ across that range — the lower half, G3b, generally calls for closer follow-up than the upper half. Most people who are told they have stage 3 are in the G3a band, often feel well, and have stable kidney function for years. Reading the precise eGFR within stage 3, rather than just “stage 3,” gives a more accurate sense of where things stand.
Why the Trend Matters More Than One Result
A stage is a snapshot, but kidney care is about direction. Most people in the early stages have stable filtration for years, and the aim of monitoring is to catch a falling trend early. A clinician usually looks at a series of eGFR results over months to years, together with albuminuria, blood pressure, and overall health, rather than reacting to a single reading. A value that holds steady is reassuring even when it sits in a lower stage; a value that is sliding deserves a closer look. If your most recent result was below range, see what a low eGFR means in context.
What Each Stage Means for Care
The stage broadly guides how closely kidney function is watched. In the earliest stages, the focus is on the underlying cause — usually blood pressure or diabetes — and on rechecking albuminuria. From stage 3 onward, monitoring becomes more regular, medications are reviewed for any that need dose adjustment, and cardiovascular risk is managed. By stage 4, care is typically shared with a kidney specialist, and there is time to plan ahead calmly. Stage 5 is kidney failure, where treatment options including dialysis or transplant are discussed based on symptoms rather than a single number. None of this is decided by the stage alone; it is set by your clinician using the full picture of your health.
Why Staging Pairs GFR With Albuminuria
A GFR category alone does not capture the whole picture, which is why full KDIGO staging adds an albuminuria category (A1–A3) alongside the G1–G5 number. Two people with an identical eGFR of 50 can sit in very different risk bands: one with minimal protein in the urine is at modestly increased risk, while one losing heavy amounts of albumin is at high risk and warrants closer follow-up. Albuminuria predicts how fast kidney function is likely to fall, independently of the current eGFR, so it earns its own axis in the staging grid rather than being folded into the GFR number.