Abstract: Objective To clarify the significance of early detection of neutrophil gelatinase-associated lipocalin (NGAL) in the diagnosis of acute kidney injury (AKI) in cirrhotic patients and the significance of NGAL-based model in differentiating the types of AKI. Methods A total of 804 patients with decompensated cirrhosis were included in the study. 213 patients (26.5%) were hospitalized with AKI or had AKI at admission. Once AKI occurred, the patients were diagnosed and treated according to the new ICA(International-Club of Ascites)-AKI guidelines. Blood aldosterone and angiotensin Ⅱ levels of the patients in the lying position in the morning were detected within 24 hours after the diagnosis of AKI. Urine NGAL (uNGAL) level was detected in the supernatant of centrifuged morning urine. The significance of NGAL in the diagnosis of AKI was evaluated and data were collected to develop an early differential diagnosis system. Results The uNGAL of cirrhotic patients with AKI was higher than that of decompensated cirrhotic patients without AKI (t=11.439, P=0.000); the levels of uNGAL were significantly different within pre-azotemia (PRA,323.08±106.93), hepatorenal syndrome (HRS,486.27±164.67) and acute tubular necrosis patients(ATN,882.43±440.92 ng/mL) (F=48.774,P=0.000). After further stratification with AKI stage, uNGAL was found to be meaningful in differentiating AKI above stage 2,especially ATN. The threshold determined by Yoden index under receiver operating characteristic curve(ROC)is 522.72ng/mL (sensitivity: 0.938, specificity: 0.655).The threshold of 621.73ng/mL (sensitivity: 0.750, specificity: 0.800) showed a higher sensitivity and was more fit for clinical requirement. The expression levels of aldosterone and angiotensin II were different in different types of AKI (P=0.000), but the intergroup analysis and multivariate analysis showed little significance for differentiating HRS from ATN. Conclusion As a new marker, uNGAL is useful for diagnosing AKI in cirrhotic patients. Early detection of uNGAL is of greater significance for differentiating ATN-type AKI.

Key words: Acute kidney injury in cirrhosis, Neutrophil gelatinase ester transporter, Differential diagnosis