Table 1

The Acute Kidney Injury Network (AKIN) criteria for the definition and classification of AKI (modified RIFLE criteria)43 47

AKI stageSerum creatinine criteriaUrine output criteria
1 (Risk)Increase in serum creatinine of ≥26.4 μmol/l (≥0.3 mg/dl) within 48 h or an increase of ≥150–200% (1.5–2-fold) from baseline<0.5 ml/kg/h for >6 h
2 (Injury)Increase in serum creatinine to 200–299% (>2–3-fold) from baseline<0.5 ml/kg/h for >12 h
3 (Failure)Increase in serum creatinine to ≥300% (>3-fold) from baseline or serum creatinine of ≥354 μmol/l (≥4.0 mg/dl) with an acute increase of ≥44 μmol/l (≥0.5 mg/dl) or initiation of renal replacement therapy<0.3 ml/kg/h for 24 h or anuria for 12 h