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Draft: not yet reviewed by a clinician

Use this page to prepare questions for your care team. It does not replace their advice. Your own targets and doses come from your nephrologist, diabetes team and renal dietitian.

CKD stages: G and A categories

In short

Kidney teams describe CKD with two labels: a G category from your eGFR (how well your kidneys filter) and an A category from your UACR (how much albumin leaks into your urine) (KDIGO 2024, Tables 2–3). Together they read like "G3a A2". The risk of kidney failure and of heart problems goes up both as eGFR falls and as albumin rises, so both numbers matter (KDIGO 2024, chapter 2). Stages are labels for planning, not a countdown. Your team can also work out your personal risk of kidney failure from a tested equation.

Your numbers

G categories: filtering (eGFR)

eGFR comes from a blood test for creatinine, plus your age and sex (NKF; CKD-EPI 2021 equation); UACR comes from a urine sample (NIDDK). The eGFR unit is the same everywhere: mL/min/1.73 m².

Category eGFR KDIGO term Your stage page
G1 90 or more normal or high G1 and G2
G2 60–89 mildly decreased G1 and G2
G3a 45–59 mildly to moderately decreased G3a
G3b 30–44 moderately to severely decreased G3b
G4 15–29 severely decreased G4
G5 under 15 kidney failure G5 without dialysis, or your dialysis or transplant page

G1 and G2 count as CKD only if there is also a sign of damage, such as albumin in the urine (KDIGO 2024, Table 2).

A categories: albumin in the urine (UACR)

Category UACR KDIGO term
A1 under 30 mg/g normal to mildly increased
A2 30–300 mg/g moderately increased
A3 over 300 mg/g severely increased
Category UACR KDIGO term
A1 under 3 mg/mmol normal to mildly increased
A2 3–30 mg/mmol moderately increased
A3 over 30 mg/mmol severely increased

Source: KDIGO 2024, Table 3. More on the test itself: UACR.

How the two combine

These examples show why both numbers count. Risk here means the chance of kidney failure, heart problems and death compared with people without CKD (KDIGO 2024, chapter 2).

Example results Categories What it means
eGFR 75, UACR 10 mg/g, no other damage not CKD an eGFR of 60–89 is not CKD on its own; keep yearly checks if you have diabetes
eGFR 75, UACR 120 mg/g G2 A2 CKD. Albumin is the early sign in diabetes. With diabetes, a kidney-protecting medicine (ACE inhibitor or ARB) is recommended (KDIGO 2024, recommendation 3.6.3)
eGFR 40, UACR 15 mg/g G3b A1 high risk
eGFR 50, UACR 450 mg/g G3a A3 higher risk than the G3b A1 example, even though the eGFR is better
eGFR 22, any UACR G4 very high risk; time to plan with a nephrologist

Your risk of kidney failure (KFRE)

At G3a to G5, KDIGO recommends using a tested risk equation to estimate your own chance of kidney failure (KDIGO 2024, recommendation 2.2.1). The best known is the Kidney Failure Risk Equation (KFRE). It uses your age, sex, eGFR and UACR, and gives a 2-year and a 5-year risk. KDIGO says most people want to know this number, and asks labs to print it on the report when they can (KDIGO 2024, chapter 2).

Your KFRE result What KDIGO suggests it can be used for
5-year risk of 3–5 % or more a referral to a kidney specialist (nephrologist)
2-year risk over 10 % care from a whole team: diet advice, a medicine review, education about treatment choices, and emotional and social support (practice point 5.3.1)
2-year risk over 40 % getting ready for kidney failure: learning the options, planning dialysis access, a transplant referral

Source: KDIGO 2024, practice points 2.2.1–2.2.3, 5.3.1 and 5.4.3. KDIGO also suggests planning for a transplant or dialysis access when eGFR is under 15–20. The KFRE was built for G3 to G5 and may not be valid at G1–G2 (practice point 2.2.4).

How often to check, and when a change is real

  • eGFR and UACR at least once a year, and more often when your risk is higher and the result would change your care (KDIGO 2024, practice points 2.1.1–2.1.2). ADA says 1 to 4 times a year, depending on the stage (ADA 2026 §11, recommendation 11.1b).
  • eGFR: a change of more than 20 % from one test to the next is more than normal day-to-day variation and should be looked into (practice point 2.1.3).
  • After starting a kidney-protecting medicine, a small, early drop in eGFR is expected. An eGFR fall of more than 30 % should be looked into (practice point 2.1.4). For an ACE inhibitor or ARB, KDIGO's line is a creatinine rise of more than 30 % within 4 weeks (practice point 3.6.4).
  • UACR: a result that has doubled is more than lab variation (practice point 2.1.5).

How to work out a change: (old − new) ÷ old × 100.

  • eGFR 50 → 41: 9 ÷ 50 = 18 %. Within normal variation; check again as planned.
  • eGFR 50 → 38: 12 ÷ 50 = 24 %. More than noise: ask your team to repeat it and look for a cause, such as dehydration, an illness or a new medicine like ibuprofen.
  • UACR 80 → 170 mg/g: more than doubled. Ask what it means for your treatment.

Does age or sex change my numbers?

  • The G and A categories are the same for all adults. KDIGO notes there is still debate about using the same eGFR cut-off in older adults, but keeps one set because the risk of harm rises with each stage at every age (KDIGO 2024, introduction).
  • Age and sex go into the eGFR equation and into the KFRE, so they are already counted in those numbers (CKD-EPI 2021 equation; KDIGO 2024, chapter 2).
  • Sex changes the anemia cut-offs: hemoglobin under 13 g/dL (130 g/L) in men and under 12 g/dL (120 g/L) in women (KDIGO 2026 anemia).
  • Food goals: protein is set per kilogram of body weight and the sodium goal is the same for all adults (KDIGO 2022, recommendations 3.1.1–3.1.2). Calorie needs do change with age, sex and activity (KDOQI 2020, guideline 3.1.1). The app's "Suggest targets" uses these factors; see First setup and Targets and warnings.

What to do

  • Find your latest eGFR and UACR on your lab report and write down your G and A categories.
  • Ask your team for your KFRE 2-year and 5-year risk if you are at G3a or beyond.
  • Put your next eGFR and UACR test dates in your calendar.
  • For a UACR test, give a first-morning urine sample if you can. Hard exercise, a period, blood in the urine or a urine infection can raise the result for a short time, so tell the lab or repeat the test (KDIGO 2024, practice point 1.3.1.1 and Table 16).
  • A cooked meat or fish meal can raise creatinine for hours and make eGFR look lower. KDIGO says waiting at least 12 hours after meat or fish best avoids this, so ask whether to fast from them before your blood test. Creatine supplements also raise creatinine (KDIGO 2024, practice point 1.2.2.4).
  • If a result changes by more than the amounts above, ask what might have caused it.
  • Read your stage page (Your stage, day to day).

Examples

  • Maria, 45, type 1 diabetes for 25 years: eGFR 52, UACR 520 mg/g (59 mg/mmol). She is G3a A3. Her nephrologist starts an ACE inhibitor and talks about finerenone, because the albumin level puts her at higher risk than her eGFR alone suggests.
  • John, 72: eGFR 38, UACR 18 mg/g. He is G3b A1, which KDIGO counts as high risk. His 5-year KFRE is 2 %, so for now his family doctor checks his eGFR and UACR more often than once a year, as KDIGO advises at higher risk (KDIGO 2024, practice point 2.1.2), keeps a blood pressure plan, and will refer him if his risk rises.
  • Priya, 58, on her third year at G4: her 2-year KFRE has risen to 42 %. Her team starts education on dialysis, transplant and conservative care, and refers her for a transplant evaluation.

Ask your care team

  1. What are my G and A categories today, and what were they a year ago?
  2. What is my KFRE 2-year and 5-year risk?
  3. How often will you check my eGFR and UACR?
  4. Was my last change in eGFR or UACR more than normal variation? What might explain it?
  5. At what point will you refer me to a nephrologist or a kidney team?

Get help now if…

A stage change is not an emergency on its own. Much less urine, new swelling, breathlessness or a very high potassium result can be: see Get help now.

Sources

Not yet reviewed by a clinician. Facts and sources last checked 2026-10-06.