- Identify cause of CKD (C)
- Assign GFR category (G)
- Assign albuminuria category (A)
Collectively referred to as “CGA Staging”
Assign GFR category as follows:
| GFR categories in CKD | ||
|---|---|---|
| Category | GFR ml/min/1.73 m2 | Terms |
| G1 | ≥90 | Normal or high |
| G2 | 60-89 | Mildly decreased* |
| G3a | 45-59 | Mildly to moderately decreased |
| G3b | 30-44 | Moderately to severely decreased |
| G4 | 15-29 | Severely decreased |
| G5 | <15 | Kidney failure |
| Abbreviations: CKD, chronic kidney disease; GFR, glomerular filtration rate. *Relative to young adult level. In the absence of evidence of kidney damage, neither GFR category G1 nor G2 fulfill the criteria for CKD. | ||
Assign Albuminuria category as follows:
| Albuminuria categories in CKD | ||
|---|---|---|
| Category | ACR (mg/g) | Terms |
| A1 | <30 | Normal to mildly increased |
| A2 | 30-300 | Moderately increased* |
| A3 | >300 | Severely increased** |
| Abbreviations: ACR, albumin-to-creatinine ratio; CKD, chronic kidney disease. *Relative to young adult level. **Including nephrotic syndrome (albumin excretion ACR >2220 mg/g) | ||
**Collectively referred to as “CGA Staging”
Identify Cause of CKD:
- Cause of CKD is classified based on presence or absence of systemic disease and the location within the kidney of observed or presumed pathologic-anatomic findings on kidney biopsy or imaging.
- Determining the cause of CKD distinguishes whether the patient has a systemic condition or a localized condition in the kidney such as glomerular disease because this functionality affects management.
- It is anticipated that the cause of disease will not be known with certainty for many patients with CKD but can be either inferred or not known.
| Examples of systemic diseases affecting the kidney | Examples of primary kidney diseases (absence of systemic diseases affecting the kidney) | |
|---|---|---|
| Glomerular diseases | Diabetes, systemic autoimmune diseases, systemic infections, drugs, neoplasia (including amyloidosis) | Diffuse, focal or crescentic proliferative glomerulonephritis; focal and segmental glomerulosclerosis; membranous nephropathy, minimal change disease |
| Tubulointerstitial diseases | Systemic infections, autoimmune, sarcoidoisis, drugs, urate, environmental toxins (lead, aristolochic acid), neoplasia (myeloma) | Urinary-tract infections, stones, obstruction |
| Vascular diseases | Atherosclerosis, hypertension, ischemia, cholesterol emboli, systemic vasculitis, thrombotic microangiopathy, systemic sclerosis | ANCA-associated renal limited vasculitis; fibromuscular dysplasia |
| Cystic and congenital diseases | Polycystic kidney disease, Alport’s syndrome, Fabry’s disease | Renal dysplasia, medullary cystic disease, podocytopathies |
| Genetic diseases are not considered separately because some diseases in each category are now recognized as having genetic determinants. | ||