A Troponin for the Kidney: Not There Yet

The reclassification of the syndrome formerly known as “acute renal failure” as “acute kidney injury” (AKI) has generated considerable interest since the initial publication of the RIFLE (Risk Injury Failure Loss End-stage) criteria and subsequent modifications by the AKI Network (AKIN) [1, 2]. This interest is reflected in the number of publications citing AKI which has increased from less than 60 in 2004 to over 700 in 2010. The genesis of this ‘rebranding’ stems from the desire to have robust criteria to enable research questions to be answered, coupled with the realization that even relatively small changes in serum creatinine (sCr) translate into a significantly poorer outcome for patients. It is this observation that has stimulated such international interest in the ‘AKI Epidemic’.