CKD Staging: G Categories and What Changes at Each Stage

Chronic kidney disease is not a single condition — it is a spectrum. Staging tells you where you are on that spectrum and, more importantly, what to do about it.

When your doctor says "you have stage 3 CKD," they are giving you specific, actionable information. Your stage determines how often you need blood tests, which medications are appropriate, whether dietary changes are needed, and when to start planning for potential future treatments like dialysis or transplant.

Understanding your stage also helps you make sense of your prognosis. Stage 2 CKD and stage 4 CKD are very different situations requiring very different responses. Knowing the difference helps you focus your energy where it matters most.

Modern CKD staging uses the CGA framework, established by KDIGO (Kidney Disease: Improving Global Outcomes). CGA stands for:

• C — Cause of kidney disease (diabetes, hypertension, glomerulonephritis, PKD, etc.)
• G — GFR category (G1 through G5, based on your eGFR)
• A — Albuminuria category (A1, A2, or A3, based on protein in your urine)

Why all three? Because two patients with the same eGFR can have very different prognoses depending on the cause and the amount of protein in their urine. A patient with G3a and A1 (moderate GFR drop, no protein leak) has a much better outlook than someone with G3a and A3 (same GFR but significant protein leak).

Your full CKD classification might look something like: "CKD G3b A2, due to diabetic nephropathy." This single line tells your care team everything they need to know about your current kidney health.

eGFR: 90 or above

This may sound contradictory — how can you have kidney disease with a normal GFR? The answer is that kidney damage can exist before filtration declines. Stage G1 CKD means your kidneys are still filtering well, but there is evidence of damage from other markers:

• Protein in the urine (albuminuria)
• Blood in the urine (haematuria)
• Structural abnormalities visible on imaging (cysts, scarring, small kidneys)
• A kidney biopsy showing damage

What happens at this stage: Your doctor will want to identify the cause, control risk factors (especially blood pressure and blood sugar), and monitor you regularly. This is the stage where intervention has the most potential to prevent progression.

How it feels: Most patients at G1 feel completely normal. You likely discovered the problem through routine screening.

eGFR: 60–89

Like G1, stage G2 is only classified as CKD if there are other signs of kidney damage (albuminuria, structural abnormalities, etc.). An eGFR of 60–89 alone — without other markers — may simply reflect normal variation or age-related decline and is not automatically CKD.

This is an important distinction. Many older adults have an eGFR in this range as a normal part of ageing. If your urine tests are normal and imaging is unremarkable, your doctor may reassure you that monitoring is all that is needed.

What happens at this stage: Focus on controlling modifiable risk factors — blood pressure, blood sugar (if diabetic), and cardiovascular health. Your doctor will check eGFR and uACR at regular intervals (typically annually) to watch for any progression.

How it feels: No symptoms. Kidney function is still very close to normal.

eGFR: 45–59

Stage G3a is where kidney disease becomes an independent diagnosis — an eGFR persistently below 60 defines CKD regardless of other markers. This is often when patients are first referred to a nephrologist.

What changes:

• Monitoring increases — Blood tests every 3–6 months instead of annually
• Medication review — Your doctor may start or adjust blood pressure medications (ACE inhibitors or ARBs), and add an SGLT2 inhibitor if appropriate
• Cardiovascular focus — CKD significantly increases heart disease risk. Cholesterol, blood pressure, and heart health become priorities
• Diet awareness — Not usually strict restrictions yet, but awareness of sodium intake and overall nutrition becomes important

How it feels: Most patients still feel fine at G3a. Some may notice mild fatigue, but many have no symptoms at all.

Prognosis: Many patients with G3a remain stable for years or even decades with good management. Progression to kidney failure is possible but far from inevitable at this stage.

eGFR: 30–44

The split between G3a and G3b is clinically significant. Patients at G3b have a substantially higher risk of progressing to kidney failure compared to G3a. This is the stage where kidney disease management becomes more active.

What changes:

• More frequent monitoring — Blood tests every 3–4 months
• Dietary adjustments — Depending on lab results, you may need to start watching potassium, phosphorus, or protein intake. A referral to a renal dietitian is common
• Medication adjustments — Some medications are dose-adjusted or changed. NSAIDs (ibuprofen, naproxen) should be avoided
• Anaemia screening — The kidneys may be producing less EPO, so haemoglobin levels are monitored
• Bone health — Calcium, phosphorus, and PTH are checked as CKD-MBD can begin developing
• Education — Your team may begin discussing future treatment options (dialysis types, transplant) so you can make informed decisions when the time comes

How it feels: Some patients begin noticing fatigue, mild swelling, or changes in urination. Others still feel well. Symptoms vary widely.

eGFR: 15–29

Stage G4 is a pivotal point. Kidney function is significantly impaired, and active preparation for potential kidney replacement therapy (dialysis or transplant) becomes a priority — even though you may not need it immediately.

What changes:

• Close monitoring — Blood tests every 1–3 months
• Transplant evaluation — If transplant is an option, the evaluation process should begin now. Getting on the waiting list early or finding a living donor takes time
• Dialysis access planning — If dialysis is likely, your doctor may recommend creating an AV fistula 6–12 months before you might need it. A fistula needs time to mature
• Stricter dietary management — Potassium, phosphorus, sodium, and sometimes protein and fluid restrictions may become necessary based on lab values
• Symptom management — Anaemia treatment (EPO injections, iron), blood pressure optimisation, acidosis correction (bicarbonate supplements), and bone health management
• Vaccination — Hepatitis B vaccination is recommended before starting dialysis

How it feels: Many patients at stage 4 experience fatigue, reduced appetite, swelling, and difficulty concentrating. Some may have nausea or itching. These symptoms are caused by the buildup of waste products (uraemia) and fluid.

eGFR: Below 15

Stage G5 is kidney failure — also called end-stage kidney disease (ESKD). At this stage, the kidneys cannot sustain life on their own, and treatment is essential.

Treatment options:

• Haemodialysis — Blood filtered through an external machine, typically 3 times per week at a dialysis centre
• Peritoneal dialysis — Home-based dialysis using the abdominal lining as a filter, performed daily
• Kidney transplant — The preferred long-term treatment for eligible patients. A pre-emptive transplant (before starting dialysis) is ideal when possible
• Conservative management — For patients who choose not to pursue dialysis (often elderly patients with significant other health conditions), supportive care focuses on comfort and quality of life

When does dialysis start? Not everyone at G5 starts dialysis immediately. The decision is based on symptoms, lab values, fluid status, and overall health — not just the eGFR number. Some patients feel relatively well at eGFR 12 and can wait. Others need to start at eGFR 15 because of severe symptoms.

How it feels: Symptoms are often significant: profound fatigue, nausea, poor appetite, swelling, itching, difficulty sleeping, and difficulty concentrating. Many patients describe feeling dramatically better once dialysis begins and waste products are cleared.

The G stage tells you how well your kidneys are filtering. The A category tells you how much protein is leaking through. Both are essential for understanding your CKD.

Albuminuria is measured by the uACR (urine albumin-to-creatinine ratio) test — a simple urine sample:

• A1 — Normal to mildly increased (uACR below 30 mg/g): Minimal or no protein leak. Best prognosis within any G stage
• A2 — Moderately increased (uACR 30–300 mg/g): Significant protein leak that indicates kidney damage and increases risk of progression. Previously called "microalbuminuria"
• A3 — Severely increased (uACR above 300 mg/g): Major protein leak indicating substantial kidney damage. Associated with faster decline and higher cardiovascular risk. Previously called "macroalbuminuria"

Why it matters: Albuminuria is not just a marker — it is a driver of kidney damage. Protein leaking through the filters causes inflammation and scarring in the kidney, accelerating progression. This is why reducing albuminuria (with ACE inhibitors, ARBs, or SGLT2 inhibitors) is a core treatment goal.

KDIGO provides a colour-coded risk matrix that combines your G stage and A category to predict your risk of progression and guide how frequently you should be monitored:

• Green (low risk) — G1-G2 with A1. Monitor annually
• Yellow (moderately increased risk) — G1-G2 with A2, or G3a with A1. Monitor 1–2 times per year
• Orange (high risk) — G3a with A2, G3b with A1-A2, or G1-G2 with A3. Monitor 2–3 times per year
• Red (very high risk) — G4-G5 any A category, G3a-G3b with A3. Monitor 3–4+ times per year

This matrix is one of the most useful tools in kidney care. It tells both you and your doctor how urgently your CKD needs attention. Ask your doctor where you fall on the matrix — it provides much more nuance than the G stage alone.

Here is a simplified summary of how your care plan evolves:

• G1–G2: Identify cause, control blood pressure and blood sugar, annual monitoring, heart health focus
• G3a: Nephrologist referral, more frequent labs, medication review, SGLT2 inhibitor consideration, dietary awareness
• G3b: Renal dietitian referral, potassium/phosphorus monitoring, anaemia screening, education about future options
• G4: Transplant evaluation, dialysis access planning, stricter dietary management, symptom treatment, vaccination
• G5: Treatment initiation (dialysis or transplant), intensive symptom management, or conservative care planning

The progression from one stage to the next is not inevitable. With proper treatment, many patients stabilise and remain at the same stage for years. The transition points where care changes most significantly are at G3a (when CKD is definitively diagnosed), G3b (when complications begin to develop), and G4 (when treatment planning becomes urgent).

Yes — and this is one of the most empowering messages in kidney care. CKD progression is not a one-way street at a fixed speed. The rate of decline can be significantly slowed, and in some cases, function can stabilise or even improve slightly.

Evidence-based strategies that slow progression:

• Blood pressure control — Target below 130/80 mmHg. This is the single most impactful modifiable factor
• ACE inhibitors or ARBs — These medications protect the kidneys beyond just lowering blood pressure. They reduce protein leak and slow scarring
• SGLT2 inhibitors — Newer medications shown to slow CKD progression by 30–40% in major clinical trials (DAPA-CKD, EMPA-KIDNEY). Now recommended for most CKD patients
• Blood sugar control — For diabetic patients, keeping HbA1c in target range reduces kidney damage
• Avoid NSAIDs — Ibuprofen, naproxen, and similar drugs can harm kidney function. Use paracetamol (acetaminophen) instead
• Sodium restriction — Reducing salt intake to under 2,000 mg/day helps blood pressure and reduces fluid retention
• Smoking cessation — Smoking accelerates kidney function decline
• Healthy weight — Obesity increases the workload on kidneys

The earlier these strategies are implemented, the more effective they are. If you are at G1–G3a, you have the greatest opportunity to change your trajectory. But even at later stages, these interventions still provide meaningful benefit.