Journal of Nephrology & Therapeutics

Urinary NGAL in Prediction of Acute Kidney Injury

Abstract

Nilgün Tekkeşin*

The incidence of acute kidney injury (AKI, previously referred to as acute renal failure) is reaching epidemic pro- portions. In this situation, early intervention can significantly improve the prognosis. Despite significant improvements in therapeutics, the mortality and morbidity associated with AKI remain high. A major reason for this is the lack of early markers for AKI, akin to troponins in acute myocardial disease, and hence an unacceptable delay in initiating therapy. Unfortunately, serum creatinine (SCr) is a delayed and unreliable indicator of AKI. The authors have previo - usly shown that urine neutrophil gelatinase-associated lipocalin (NGAL) is an early predictive biomarker of acute kid- ney injury (AKI) after cardiopulmonary bypass (CPB). In this study, the evidence for the role of NGAL measurements in AKI after CPB is explored. The emerging utility of standardized clinical platforms for reliable measurement of NGAL urine is discussed. In a prospective study with 303 adults undergoing CPB were enrolled and serial urine NGAL me- asurements were obtained. The primary outcome was AKI, defined as a >50% increase in SCr. AKI developed in 75 patients (25%), but the diagnosis using Scr was delayed by 2 to 3 d after CPB. In contrast, mean urine NGAL levels increased 4-fold within 2 h after CPB and remained significantly elevated for the duration of the study. The 2-h posto - perative urine NGAL levels strongly correlated with change in creatinine (r =0.56, p<0.001), duration of AKI (r =0.47, p<0.001), and length of hospital stay ( r =0.39, p<0.001). The 12-h urine NGAL levels stromgly correlated with death (r=0.41, p<0.004). Urine NGAL is an early predictive biomarker of AKI severity and mortality after CPB. It will be impor - tant in future studies to validate the sensitivity and specificity of NGAL concentration measurements in clinical samp - les from large cohorts and from multiple clinical situations. Such studies will be facilitated by the anticipated widesp - read availability of standardized commercial tools in the near future.