Direct Measurement of Creatinine Clearance over a Short Interval in Intensive Care Settings.

Background: The definition of acute kidney injury (AKI), based on serum creatinine and urine output, bears significant limitations in intensive care units (ICUs). Serum creatinine has significant lag-time as it needs to be accumulated and stabilized at a new level whereas urine output is affected by diuresis, antidiuresis, and antinatriuresis. Direct measurement of creatinine clearance (CrCl = urine creatinine × urine flow rate/serum creatinine) over a short interval (3-6 hours) was explored to identify patients with AKI.