Table 4.

AKIN (acute kidney injury network) classification consider AKI stage 1 an increase of more than or equal to 0.3 mg/dL (26.5 mmol/L) or increase from baseline to more than or equal to 1.5- to 2-fold within a 48 h period

Rifle classification	Urinary output	AKIN classification
Risk increase in serum creatinine × 1.5 or GFR decreased >25 %	<0.5 mL/kg/h for more than 6 h	Stage 1 increase ≥0.3 mg/dL or ≥1.5 from baseline
Injury Increase in serum creatinine × 2 or GFR decreased >50 %	<0.5 mL/kg/h for more than 12 h	Stage 2 Increase >2- to 3-fold from baseline
Failure Increase in serum creatinine x 3 or GFR decreased >75 %	<0.3 mL/kg/h for 24 h or anuria for 12 h	Stage 3 increase >3-fold from baseline or on RRT
Loss persistent acute renal failure >4 weeks
End-stage kidney disease ESRD >3 months

The RIFLE classification, in which the first class considers only serum creatinine increase of 0.5 mg/dL within a period of 1–7 days