Acute kidney injury classification: AKIN and RIFLE criteria in critical patients

Table 1 Risk of renal failure, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage renal failure and Acute Kidney Injury Network classification schemes for acute kidney injury

	GFR criteria	Urine output criteria
RIFLE (an acute rise in SCr over 7d)
Risk	Increase in SCr ≥ 1.5 × baseline or decrease in GFR ≥ 25%	UO < 0.5 mL/kg per hour × 6 h
Injury	Increase in SCr ≥ 2.0 × baseline or decrease in GFR ≥ 50%	UO < 0.5 mL/kg per hour × 12 h
Failure	Increase in SCr ≥ 3.0 × baseline or SCr ≥ 4.0 mg/dL (354 μmol/L) or decrease in GFR ≥ 75%	UO < 0.3 mL/kg per hour × 24 h or anuria × 12 h
Loss	Complete loss of kidney function > 4 wk
ESKD	End stage renal disease (> 3 mo)
AKIN (an acute rise in SCr within 48 h)
Stage 1	Same as RIFLE-Risk plus increase in SCr ≥ 0.3 mg/dL (≥ 26.4 μmol/L)	Same as RIFLE
Stage 2	Same as RIFLE-Injury
Stage 3	Same as RIFLE-Failure plus initiation of RRT

AKIN: Acute Kidney Injury Network; ESKD: End-stage kidney disease; GFR: Glomerular filtration rate rate; RIFLE: Risk of renal failure, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage renal failure; RRT: Renal replacement therapy; SCr: Serum creatitine; UO: Urine output.