Table 1.

Classification of acute kidney injury by RIFLE, AKIN and KIDGO criteria[12,28,36]

Stage	Glomerular filtration rate (GFR) criteria	Urine output criteria
RIFLE classification
Risk	Serum creatinine increased x 1.5 or GFR decrease >25%	<0.5 ml/kg/hr for ≥ 6 hours
Injury	Serum creatinine increased x 2 or GFR decrease >50%	<0.5 ml/kg/hr for ≥ 12 hours
Failure	Serum creatinine increased x 3 or GFR decrease ≥ 75% or an absolute serum creatinine ≥ 354 μmol/L with an acute rise ≥ 4 μmol/L	<0.3 ml/kg/hr for ≥ 24 hours or anuria for ≥12 hours
Loss	Persistent AKI, requiring RRT for > 4 weeks
End-stage kidney disease	Requiring dialysis > 3 months
AKIN classification
Stage 1	Serum creatinine increased ≥26.2 μmol/L or x 0.5 to 2 baseline	<0.5 ml/kg/hr for ≥ 6hours
Stage 2	Serum creatinine increased x 2 to 3 baseline	<0.5 ml/kg/hr for ≥ 12 hours
Stage 3	Serum creatinine increased > x 3 baseline or serum creatinine ≥ 354 μmol/L with an acute rise ≥ 44 μmol/L or initiation of RRT	<0.3 ml/kg/hr for ≥ 24 hours or anuria for ≥12 hours
KDIGO classification
Stage 1	Serum creatinine increased x 1.5 to 1.9 baseline or by ≥ 26.2 μmol/L	<0.5 ml/kg/hr for 6 to 12 hours
Stage 2	Serum creatinine increased x 2 to 2.9 baseline	<0.5 ml/kg/hr for ≥ 12 hours
Stage 3	Serum creatinine increased > x 3 baseline or serum creatinine ≥ 354 μmol/L with an acute rise ≥ 44 μmol/L or initiation of RRT	<0.3 ml/kg/hr for ≥ 24 hours or anuria for ≥12 hours

AKIN, Acute Kidney Injury Network; KDIGO, Kidney Disease: Improving Global Outcomes.