[Acute kidney injury after cardiac surgery : early diagnosis with neutrophil gelatinase-associated lipocalin].

In current clinical practice, the diagnosis of acute kidney injury (AKI) is based on markers of renal function, e.g., an increase in serum creatinine or a decrease in urine output. Biomarkers for the early detection of structural renal damage are still not available. This dilemma may have considerably contributed to the delayed development of effective therapies and poor prognosis for the affected patients. The measurement of novel renal damage biomarkers, such as neutrophil gelatinase-associated lipocalin (NGAL), enables a 24 to 48-hour earlier diagnosis of AKI after cardiac surgical procedures. Based on the presence of a biomarker, potentially effective treatments may be initiated or nephrotoxins withdrawn. In addition, NGAL may also provide valuable information for patient management. Currently, no clear NGAL cut-off has been established, thus, impeding its clinical implementation. Prior to a change of guidelines, multicenter randomized studies, using NGAL as an entry criterion, should prove a benefit for the patients or a favorable cost-benefit ratio.