Modern classification of acute kidney injury.

Acute kidney injury (AKI) is a common clinical syndrome defined as a sudden onset of reduced kidney function manifested by increased serum creatinine or a reduction in urine output. This clinical syndrome has been called by 25 different names and at least 35 definitions. As a result of this deficiency of standardized definition, reported incidences of AKI in the ICU range from 1 to 25% with mortality rates between 15 and 60%. This lack of a uniform definition not only leads to the conflicting reports in the literature but is also a major obstacle for research in the field. The recent consensus definition which was proposed by the ADQI group and expanded by AKIN has brought the RIFLE criteria and staging into position as the standard definition and diagnosis of this syndrome. The RIFLE criteria have been extensively validated in more than 550,000 patients worldwide.