Study protocol
AKI
We established an independent study group to screen patients admitted to the ICU for AKI and collect specimens and perform FST on patients who satisfied the inclusion criteria but did not match the exclusion criteria. The responsible physician and the patient were both blinded to the 2-h urine volume following FST. Patients are not notified of any changes in urine volume following an FST. The study team blinded the physicians by covering the urine bag with an opaque paper bag for 2 h, recording the 2-h urine volume, and then discarding the urine.When the blinding was revealed, the urine volume 2 h after FST was withheld from the critical care record sheet until the patient initiated CRRT or was transferred out of the ICU, at which point the urine volume 2 h after FST was added to the record sheet.