C1orf146 and acute kidney injury: In clinical practice, critical variations, defined by an absolute increase of 0.3 mg/dL (26.5 μmol/L) in S-Cre within 48 hours or a 50% increase in S-Cre concentration over a 7-day period, have been used to diagnose in-hospital acute kidney injury (AKI) since 20041,2.