Urinary NGAL to define AKI in asphyxiated infants.

Acute kidney injury (AKI) is independently associated with poor outcomes in the critically ill patient. The standard kidney function biomarker, serum creatinine, shows a demonstrable rise in concentration many hours to days after insult to the kidney. Thus, creatinine-based AKI diagnosis is likely delayed, rendering treatments to mitigate or prevent AKI ineffective. Neonatal AKI is further confounded by the fact that infant serum creatinine concentrations reflect maternal levels. The past 15 years has seen a massive research effort to identify early damage markers of AKI, with the hope that earlier "sub-clinical" AKI diagnosis can lead to earlier initiation of AKI treatment, or to adjustment of care to mitigate the adverse effects of AKI until renal function recovery occurs. One of the most promising urinary AKI biomarkers, neutrophil gelatinase associated lipocalin (NGAL), has repeatedly performed well to predict AKI in many pediatric populations, including those post-cardiac surgery, critically ill mechanically ventilated children and children arriving to the emergency department. The study reported by Admani et al. uses NGAL not only to predict serum creatinine-based AKI, but also to define AKI to associate a Day 1 NGAL concentration above a specific threshold with clinical outcomes.