N-GAL: Diagnosing AKI as soon as possible

Early diagnosis of acute kidney injury (AKI) is often problematic, due to the lack of suitable early biomarkers of renal damage and kidney function. Neutrophil gelatinase-associated lipocalin (NGAL) as an early marker of AKI partially overcomes such limitations and seems to demonstrate that diagnosing AKI in its early stages is possible and useful. Using genomic and protein microarray technology, a series of molecules have been identified as potential markers for AKI; among them NGAL has been demonstrated to rise significantly in patients with AKI but not in the corresponding controls. Furthermore, this rise in NGAL occurs in various studies at 24 to 48 hours before the rise in creatinine is observed. NGAL both in urine and plasma is an excellent early marker of AKI with an area under the receiver operator characteristic curve (AUC) in the range of 0.9. The study of Zappitelli et al. in critically ill children combines for the first time the new RIFLE classification (Risk, Injury, Failure, Loss, End-stage renal disease) of AKI with the validation of NGAL as an early marker of kidney injury. This innovative approach brings a new hope for a timely diagnosis of AKI and thus a timely institution of measures for prevention and protection.