Table 1.

Classifications of Acute Kidney Injury and Chronic Kidney Disease.^*

Stage	Assessments
Acute kidney injury	Serum Creatinine Concentration	Urine Output
1	1.5–1.9× baseline or ≥0.3 mg/dl above baseline	<0.5 ml/kg/hr for 6–12 hr
2	2.0–2.9× baseline	<0.5 ml/kg/hr for >12 hr
3	≥3.0× baseline, ≥4.0 mg/dl, or initiation of renal-replacement therapy	<0.3 ml/kg/hr for ≥24 hr or anuria for ≥12 hr
Chronic kidney disease	Definition	GFR
		ml/min/1.73 m 2
1	Kidney damage with normal GFR	≥90
2	Kidney damage with mild decrease in GFR	60–89
3A	Mild-to-moderate decrease in GFR	45–59
3B	Moderate-to-severe decrease in GFR	30–44
4	Severe decrease in GFR	15–29
5	End-stage renal disease	<15

^*The stage of acute kidney injury is determined according to the Kidney Disease Improving Global Outcomes Acute Kidney Injury Classification,⁶ and that of chronic kidney disease according to the glomerular filtration rate (GFR).² Kidney damage is usually detected by means of an increased urinary albumin-to-creatinine ratio. To convert the values for creatinine to micromoles per liter, multiply by 88.4.