Saour M, Zeroual N, Ridolfo J, et al. - This prospective, single center, observational study was performed to determine alterations in serum phosphate (SPh) during acute kidney injury (AKI) post- cardiac surgery as well as to investigate the accuracy for the diagnosis of AKI severity as well as recovery. In this study, all patients admitted consecutively to the ICU between February 2015 and March 2016 participated. Of overall 260 patients, 86 developed AKI. AKI patients demonstrated a significant rise of SPh values, which peaked at 48 hours. At this time, a good accuracy for AKI severity was shown by an SPh of 1.33 mmol/L, with an area under the curve of 0.91. Overall, findings revealed that SPh alterations closely followed AKI severity as well as kidney recovery following cardiac surgery. It was also inferred that early favorable result may be predicted with the help of this simple biological marker, besides serum creatinine.