| Stage | GFR criteria | Urine output criteria |
| Mnemonic | 1, 2, 3, 4 | 1, 2, 3 |
| 1. Risk | Cr ↑ 1.5-2 X GFR ↓ 25-50% (>1/4) | <0.5 ml/kg/hr X 6-12 (>1/4 day) |
| 2. Injury | Cr ↑ 2-3 X GFR ↓ >50-75% (>2/4) | <0.5 ml/kg/hr X >12-24 hrs (>2/4 day) |
| 3. Failure | Cr ↑ >3 X Cr ↑ 0.5 mg/dl to >4 mg/dl GFR ↓ >75% (>3/4) | <0.3 ml/kg/hr X >/= 24 hrs Anuria >12 hrs |
| 4. Loss | Need for dialysis >4 weeks | |
| 5. ESRD | Need for dialysis >3 months |
This system has a separate criteria for creatinine and urine output. If the patient’s condition falls under two different levels, then the worse classification should be used.
RIFLE-FC = denotes ‘acute-on-chronic’ disease.
RIFLE-FO = when RIFLE-F classification is reached by urine output criteria only