Table 1.

Proposed classification scheme for acute kidney injury (AKI) in patients^*

Stage	Creatinine criteria	Urine output criteria
1 (Risk)	Increased SCr of ≥0.3 mg dl⁻¹ or increase to ≥150%−200% from baseline	UO <0.5 ml kg⁻¹ h⁻¹ for >6 h
2 (Injury)	Increased SCr to >200%−300%	UO <0.5 ml kg⁻¹ h⁻¹ for >12 h
3 (Failure)	Increase SCr to >300% from baseline (or Scr ≥4 mg dl⁻¹) (acute rise ≥0.5 mg/dl)	UO <0.3 ml kg⁻¹ h⁻¹ × 24 h or Anuria × 12 h
Stages eliminated from the original RIFLE criterion
Loss	Persistent ARF = complete loss of kidney function >4 weeks
ESKD	End-stage kidney disease (>3 months)

ARF: Acute renal failure; ESKD: end-stage kidney disease; RIFLE: Risk of renal dysfunction; injury to the kidney; failure of kidney function; loss of kidney function; end-stage kidney disease; SCr: serum creatinine; UO: urine output.

Adapted from Reference 23.