Defining AKI

AKI is a type of kidney disease defined by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines as the presence of any of the following regarding increased serum creatinine (SCr) or reduced urine output12:

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

Increase in SCr to ≥1.5 times baseline within the prior 7 days (ie, known or presumed to have occurred withing this period)

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

The KDIGO guidelines for AKI, developed in 2012, consolidated the 2004 Risk, Injury, Failure, Loss of Kidney Function, and End-Stage Kidney Disease (RIFLE)14 and the 2007 Acute Kidney Injury Network (AKIN) classifications.15

Distinguishing AKI from other kidney diseases such as CKD, acute kidney disease, or no known kidney disease is important for the selection of appropriate treatment options and management strategies.