Acute kidney injury: how do we define it?

Over recent years, there has been welcome increased interest in acute kidney injury (AKI) and its association with patient outcome. The term AKI has replaced the term acute renal failure (ARF) and encompasses all types of ARF. New definitions and staging systems for AKI have been proposed, which have stimulated a multitude of different studies to evaluate their clinical utility. These recent advances need to be communicated to the wider health care community so that we are using a shared nomenclature. In 2009 the National Confidential Enquiry into Patient Outcome and Death AKI study ('Adding Insult to Injury') announced its findings and recommendations. The report recommended that the detection of AKI and its management should be improved. These recommendations along with the adoption of the new staging systems will potentially have an impact on clinical biochemistry departments and exert an increased demand on resources. Running in parallel with these initiatives is the quest to discover novel biomarkers to detect AKI, the development and introduction of which will require laboratory support.