title: The predictive performance of plasma neutrophil gelatinase-associated lipocalin (NGAL) increases with grade of acute kidney injury.
abstract: BACKGROUND
  In adult cardiac surgery, the predictive value for AKI of neutrophil gelatinase-associated lipocalin (NGAL) appears to have wide variability. The choice of definition of acute kidney injury (AKI) might, at least in part, account for such variability.
  
  
  METHODS
  In a prospective study of 100 adult cardiac surgery patients, we assessed the value of postoperative plasma NGAL in predicting AKI according to the degree of severity used for its definition.
  
  
  RESULTS
  The predictive value of plasma NGAL varied according to the AKI definition used and was higher for more severe AKI (increase in creatinine >50%: mean AUC-ROC 0.79 +/- 0.01) compared to less severe AKI (>25%: mean AUC-ROC 0.65 +/- 0.02); P = 0.001. The discriminatory ability of NGAL for AKI also increased with increasing RIFLE classes (AUC-ROC R: 0.72, I: 0.79, F: 0.80) or AKIN stages (AUC-ROC 1: 0.75, 2: 0.78, 3: 0.81); P = 0.015. It was highest for the prediction of renal replacement therapy (AUC-ROC: 0.83).
  
  
  CONCLUSIONS
  In adult cardiac surgery patients, the predictive value of NGAL increases with grade of AKI. This observation needs to be taken into account when interpreting any future studies of this biomarker.
authors.affiliation: Department of Intensive Care, Austin Health, Melbourne, Australia.
authors.forename: Anja
authors.initials: A
authors.lastname: Haase-Fielitz
authors.forename: Rinaldo
authors.initials: R
authors.lastname: Bellomo
authors.forename: Prasad
authors.initials: P
authors.lastname: Devarajan
authors.forename: Michael
authors.initials: M
authors.lastname: Bennett
authors.forename: David
authors.initials: D
authors.lastname: Story
authors.forename: George
authors.initials: G
authors.lastname: Matalanis
authors.forename: Ulrich
authors.initials: U
authors.lastname: Frei
authors.forename: Duska
authors.initials: D
authors.lastname: Dragun
authors.forename: Michael
authors.initials: M
authors.lastname: Haase
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000145:classification; D000209:Acute-Phase Proteins; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D006348:Cardiac Surgical Procedures; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D000071068:Lipocalin-2; D054834:Lipocalins / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011518:Proto-Oncogene Proteins / Q000097:blood*; D012372:ROC Curve
chemical_list: D000209:Acute-Phase Proteins; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D003404:Creatinine