Table 1.

AKI classification according to RIFLE, AKIN and KDIGO criteria [14].

	RIFLE SCr criterion		AKIN SCr criterion		KDIGO SCr crtiterion	RIFLE/AKIN/KDIGO Urine output criterion
Risk	≥1.5-fold increase from baseline SCr or decrease in GFR ≥25%	Stage 1	≥0.3 mg/dL increase or ≥1.5-fold increase from baseline SCr within 48 hrs	Stage 1	≥0.3 mg/dL increase within 48 hrs or 1.5–1.9 times the baseline within 7 days	<0.5 mL/kg/h for >6 hrs
Injury	≥2-fold increase from baseline SCr or decrease in GFR ≥50%	Stage 2	≥2-fold increase from baseline SCr	Stage 2	2.0–2.9 times the baseline within 7 days	<0.5 mL/kg/h for ≥12 hrs
Failure	≥3-fold increase from baseline SCr or increase to ≥4.0 mg/dL or decrease in GFR ≥75%	Stage 3	≥3-fold increase from baseline SCr or increase to ≥4.0 mg/dL with an acute increase of >0.5 mg/dL or initiation of RRT	Stage 3	≥3 times the baseline within 7 days or increase to ≥4.0 mg/dL with an acute increase of >0.5 mg/dL or initiation of RRT	<0.3 mL/kg/h for ≥24 hrs or anuria for ≥12 hrs
Loss	Persistent renal failure >4 weeks		–		–	–
ESRD	Persistent renal failure >3 months		–		–	–

SCr – serum creatinine; GFR – glomerular filtration rate; RRT – renal replacement therapy.