title: Neutrophil Gelatinase-Associated Lipocalin as a Diagnostic Marker for Acute Kidney Injury in Oliguric Critically Ill Patients: A Post-Hoc Analysis.
abstract: BACKGROUND
  Oliguria occurs frequently in critically ill patients, challenging clinicians to distinguish functional adaptation from serum-creatinine-defined acute kidney injury (AKIsCr). We investigated neutrophil gelatinase-associated lipocalin (NGAL)'s ability to differentiate between these 2 conditions.
  
  
  METHODS
  This is a post-hoc analysis of a prospective cohort of adult critically ill patients. Patients without oliguria within the first 6 h of admission were excluded. Plasma and urinary NGAL were measured at 4 h after admission. AKIsCr was defined using the AKI network criteria with pre-admission serum creatinine or lowest serum creatinine value during the admission as the baseline value. Hazard ratios for AKIsCr occurrence within 72 h were calculated using Cox regression and adjusted for risk factors such as sepsis, pre-admission serum creatinine, and urinary output. Positive predictive values (PPV) and negative predictive values (NPV) were calculated for the optimal cutoffs for NGAL.
  
  
  RESULTS
  Oliguria occurred in 176 patients, and 61 (35%) patients developed AKIsCr. NGAL was a predictor for AKIsCr in univariate and multivariate analysis. When NGAL was added to a multivariate model including sepsis, pre-admission serum creatinine and lowest hourly urine output, it outperformed the latter model (plasma p = 0.001; urinary p = 0.048). Cutoff values for AKIsCr were 280 ng/ml for plasma (PPV 80%; NPV 79%), and 250 ng/ml for urinary NGAL (PPV 58%; NPV 78%).
  
  
  CONCLUSIONS
  NGAL can be used to distinguish oliguria due to the functional adaptation from AKIsCr, directing resources to patients more likely to develop AKIsCr.
authors: Department of Intensive Care, Erasmus MC - University Medical Center, Rotterdam, The Netherlands.
authors: Mohamud
authors: M
authors: Egal
authors: Hilde R H
authors: HR
authors: de Geus
authors: A B Johan
authors: AB
authors: Groeneveld
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D016638:Critical Illness; D005260:Female; D006801:Humans; D000071068:Lipocalin-2 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009846:Oliguria / Q000175:diagnosis* / Q000503:physiopathology; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2