Table 3.

Classification/staging system for AKI according to AKIN [9]

Stage	Serum creatinine criteria	Urine output criteria
1	Increase in serum creatinine of ≥0.3 mg/dl (≥26.4 μmol/l) or increase to ≥150–200% (1.5-to 2-fold) from baseline	<0.5 ml/kg/h for >6 h
2	Increase in serum creatinine to >200–300% (>2-to 3-fold) from baseline	<0.5 ml/kg/h for >12 h
3	Increase in serum creatinine to >300% (>3-fold) from baseline [or serum creatinine of ≥4.0 mg/dl (≥354 μmol/l) with an acute increase of at least 0.5 mg/dl (44 μmol/l)]	<0.3 ml/kg/h for 24 h or anuria for 12 h