The predictive performance of plasma neutrophil gelatinase-associated lipocalin (NGAL) increases with grade of acute kidney injury.
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.
Haase-Fielitz
Anja
A
Department of Intensive Care, Austin Health, Melbourne, Australia.
Bellomo
Rinaldo
R
Devarajan
Prasad
P
Bennett
Michael
M
Story
David
D
Matalanis
George
G
Frei
Ulrich
U
Dragun
Duska
D
Haase
Michael
M
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
D000209:Acute-Phase Proteins; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D003404:Creatinine