[Definition and biomarkers of acute renal damage: new perspectives]

The RIFLE and AKIN criteria have definitely help out to draw attention to the relationship between a deterioration of renal function that produces a small increase in serum creatinine and a worse outcome. However, the specific clinical utility of using these criteria remains to be well-defined. It is believed that the main use of these criteria is for the design of epidemiological studies and clinical trials to define inclusion criteria and objectives of an intervention. AKI adopting term, re-summoning former ARF terminology, it is appropriate to describe the clinical condition characterized by damage to kidney, in the same way as the term is used to describe acute lung damage where the lung injury situation still has not increased to a situation of organ failure (dysfunction). The serum and urine biomarkers (creatinine, urea, and diuresis) currently in use are not sensitive or specific for detecting kidney damage, limiting treatment options and potentially compromising the outcome. New biomarkers are being studied in order to diagnose an earlier and more specific AKI, with the potential to change the definition criteria of AKI with different stages, currently based in diuresis and serum creatinine.