title: Assessment of NGAL as an early biomarker of acute kidney injury in adult cardiac surgery patients.
abstract: Early and predictive acute kidney injury (AKI) markers may be decisive for the clinical outcome of heart surgery. Hence, this study set out to evaluate the biological variability of urinary neutrophil gelatinase-associated lipocalin (uNGAL) levels in adult cardiac surgery patients, to test their feasibility as a biomarker of early AKI in a routine laboratory setting. uNGAL levels were measured with an automated immunoassay in urine samples from patients undergoing cardiac surgery using cardiopulmonary bypass, at the time of admission (T0) and 4 hours (T1) and 24 hours (T2) after surgery. Patients without post-operative AKI did not show significant differences in urine NGAL levels after surgery. In contrast, patients developing AKI displayed a significant increase (P=0.011) in uNGAL levels compared to T0. This increase was detectable at an earlier time point (T1, 4 hours) with respect to serum creatinine (T2, 24 hours). Confirming its utility as a biomarker, at T1 the uNGAL levels were significantly higher in AKI patients than in non-AKI patients (P=0.021). A receiver operating characteristic curve analysis of the uNGAL assay gave a sensitivity of 55.3 (95percent confidence interval, 26.59-78.73), a specificity of 72.9 (95 percent CI, 55.88-86.21), and a cut-off value for AKI prediction of 55.2. These results support the notion that urinary NGAL is an earlier marker of AKI than serum creatinine. However, the cut-off value of the assay was too low to consider it as a positive or negative diagnostic marker in AKI patients with moderate degree of severity. Likewise, its sensitivity and specificity were not high enough for it to be considered better than the others currently in use.
authors.affiliation: Dipartimento di Medicina Sperimentale, Sapienza Università di Roma, Rome, Italy. valeria.sargentini@uniroma1.it
authors.forename: V
authors.initials: V
authors.lastname: Sargentini
authors.forename: P
authors.initials: P
authors.lastname: Mariani
authors.forename: M
authors.initials: M
authors.lastname: D' Alessandro
authors.forename: V
authors.initials: V
authors.lastname: Pistolesi
authors.forename: M P
authors.initials: MP
authors.lastname: Lauretta
authors.forename: F
authors.initials: F
authors.lastname: Pacini
authors.forename: L
authors.initials: L
authors.lastname: Tritapepe
authors.forename: S
authors.initials: S
authors.lastname: Morabito
authors.forename: A
authors.initials: A
authors.lastname: Bachetoni
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood / Q000209:etiology / Q000652:urine*; D000209:Acute-Phase Proteins / Q000652:urine*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood / Q000652:urine; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D003404:Creatinine / Q000097:blood; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D000071068:Lipocalin-2; D054834:Lipocalins / Q000652:urine*; D008297:Male; D008875:Middle Aged; D011518:Proto-Oncogene Proteins / Q000652:urine*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; C489506:LCN2 protein, human; D000071068:Lipocalin-2; D054834:Lipocalins; D011518:Proto-Oncogene Proteins; D003404:Creatinine