. 2021 Sep 3;10(17):3991. doi: 10.3390/jcm10173991

Table 1.

Acute kidney injury (AKI) definition and staging.

AKI Definition	Serum Creatinine or GFR Criteria	Urine Output Criteria
	Increase in serum creatinine by ≥0.3 mg/dL (≥26.5 micromol/L) within 48 h, or Increase in serum creatinine to ≥1.5 times baseline, which is known or presumed to have occurred within the prior seven days, or	Urine output <0.5 mL/kg/hour for 6 h
AKI Staging	Serum Creatinine or GFR Criteria	Urine Output Criteria
Stage 1	Increase in serum creatinine to 1.5 to 1.9 times baseline, or Increase in serum creatinine by ≥0.3 mg/dL (≥26.5 micromol/L), or	Reduction in urine output to <0.5 mL/kg/hour for 6 to 12 h.
Stage 2	Increase in serum creatinine to 2.0 to 2.9 times baseline, or	Reduction in urine output to <0.5 mL/kg/hour for ≥12 h.
Stage 3	Increase in serum creatinine to 3.0 times baseline, or Increase in serum creatinine to ≥4.0 mg/dL (≥353.6 micromol/L), or Initiation of kidney replacement therapy, or In patients < 18 years, decrease in estimated glomerular filtration rate (eGFR) to <35 mL/min/1.73 m².	Reduction in urine output to <0.3 mL/kg/hour for ≥24 h, or Anuria for ≥12 h

GFR: Glomerular filtration rate; in bold or: Any one of these criteria meet the definition of AKI.