Table 1

Staging and definition of AKI according to the KDIGO guidelines in 2012

Definition	Stage	Serum creatinine	Urine output
Increase in SCr by ≥0.3 mg/dL (≥26.5 μmol/L) within 48 hours or Increase in SCr to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days or Urine volume <0.5 mL/kg/hour for 6 hours	1	1.5–1.9 times baseline or ≥0.3 mg/dL (≥26.5 μmol/L) increase	<0.5 mL/kg/hour for 6–12 hours
2	2.0–2.9 times baseline	<0.5 mL/kg/hour for ≥12 hour
3	3.0 times baseline or Increase in serum creatinine to ≥4.0 mg/dL (≥353.6 μmol/L) or Initiation of renal replacement therapy or, In patients <18 years, decrease in eGFR to <35 mL/min per 1.73 m²	<0.3 mL/kg/hour for ≥24 hours or Anuria for ≥12 hour

Definition

Stage

Serum creatinine

Urine output

Increase in SCr by ≥0.3 mg/dL (≥26.5 μmol/L) within 48 hours

Increase in SCr to ≥1.5 times baseline, which is known or presumed to have occurred within the prior 7 days

Urine volume <0.5 mL/kg/hour for 6 hours

1.5–1.9 times baseline
or
≥0.3 mg/dL (≥26.5 μmol/L) increase

<0.5 mL/kg/hour for 6–12 hours

2.0–2.9 times baseline

<0.5 mL/kg/hour for ≥12 hour

3.0 times baseline
or
Increase in serum creatinine to ≥4.0 mg/dL (≥353.6 μmol/L)
or
Initiation of renal replacement therapy
or,
In patients <18 years, decrease in eGFR to <35 mL/min per 1.73 m²

<0.3 mL/kg/hour for ≥24 hours
or
Anuria for ≥12 hour

AKI, acute kidney injury; eGFR, estimated glomerular filtration rate; SCr, serum creatinine.