Chronic kidney disease (CKD) is an abnormality of kidney structure or function present for ≥3 months. CKD is classified using both eGFR (G1–G5) and albuminuria (A1–A3).
- G1 – eGFR ≥90 mL/min/1.73 m²
- Normal or high eGFR.
- Not CKD unless there is evidence of kidney damage, such as albuminuria, renal haematuria, structural abnormality or abnormal histology.
- G2 – eGFR 60–89
- Mildly reduced eGFR.
- Not CKD unless there is evidence of kidney damage.
- G3 – eGFR 30–59
- CKD is established by the persistently reduced eGFR; albuminuria is not required.
- G3a: 45–59
- G3b: 30–44
- CKD may still be asymptomatic.
- G4 – eGFR 15–29
- Severely reduced kidney function.
- Assess complications and progression.
- Consider nephrology involvement and planning for kidney replacement therapy where appropriate.
- G5 – eGFR <15
- Kidney failure.
- Management may include dialysis, transplantation or conservative kidney management depending on symptoms, progression and patient goals.
Albuminuria
Albuminuria independently predicts CKD progression and cardiovascular risk and should be recorded alongside the eGFR stage.
- A1: uACR <3 mg/mmol
- A2: uACR 3–30 mg/mmol
- A3: uACR >30 mg/mmol
So CKD is best described as, for example:
CKD G3b A2
rather than simply “Stage 3 CKD”.
Diagnosis
CKD requires abnormalities persisting for ≥3 months:
- eGFR <60, or
- evidence of kidney damage, including:
- albuminuria
- renal haematuria after exclusion of urological causes
- structural kidney abnormality
- pathological abnormality.
Therefore:
G1/G2 + kidney damage = CKD
G3/G4/G5 = CKD from persistent eGFR reduction alone
Management
Management aims to:
- identify and treat the underlying cause
- slow CKD progression
- reduce cardiovascular risk
- control blood pressure and diabetes
- reduce albuminuria
- avoid nephrotoxins
- adjust medication doses for kidney function
- detect and treat complications
- refer to nephrology when appropriate.
- For screening and case finding: Screening for CKD