What are the stages of CKD?
Chronic kidney disease (CKD) is staged by two measures. The eGFR gives the G stage. The urine albumin:creatinine ratio (ACR) gives the A stage.
Together they predict the risk of kidney failure and cardiovascular events. NICE NG203 and KDIGO use the same system.
CKD stages by eGFR (G1–G5)
| Stage | eGFR (mL/min/1.73m²) | Description |
|---|---|---|
| G1 | 90 or more | Normal or high. CKD only with other markers of damage. |
| G2 | 60–89 | Mildly decreased. CKD only with other markers of damage. |
| G3a | 45–59 | Mildly to moderately decreased |
| G3b | 30–44 | Moderately to severely decreased |
| G4 | 15–29 | Severely decreased |
| G5 | Below 15 | Kidney failure |
Albuminuria stages (A1–A3)
| Stage | ACR (mg/mmol) | Description |
|---|---|---|
| A1 | Below 3 | Normal to mildly increased |
| A2 | 3–30 | Moderately increased |
| A3 | Over 30 | Severely increased |
When to refer (NICE NG203)
- eGFR below 30 (stage G4 or G5).
- ACR 70 mg/mmol or more, unless caused by treated diabetes.
- ACR 30 or more with persistent haematuria.
- 5-year kidney failure risk over 5% on the 4-variable KFRE.
- A sustained eGFR fall of 25% or more with a change in stage.
- A sustained eGFR fall of 15 or more within 12 months.
- Poorly controlled hypertension despite four or more drugs.
- Known or suspected rare or genetic causes of CKD.
Diagnosing CKD properly
- Confirm a low eGFR or raised ACR over at least 3 months.
- Repeat a raised ACR on an early-morning sample.
- Avoid eGFR testing within 12 hours of eating meat.
- eGFR is less reliable at extremes of muscle mass.
- Use creatinine clearance, not eGFR, to dose some drugs.