Abstract: Objective:To compare the urinary neutrophil gelatinase-associated lipocalin (NGAL) levels in the acute kidney injury (AKI) and non-AKI premature infants,and to explore the clinical value of NGAL level in the early diagnosis of AKI. Methods:A total of 85 premature infants were divided into AKI group (n=30) and non-AKI group (n=55) according to whether AKI occurred.The levels of urinary NGAL were detected by enzyme-linked immunosorbent assay (ELISA)method at 24, 48, 72, 120, and 168 h after birth. The levels of serum creatinine (Scr) of preterm infants were detected by dry chemical method.The receiver operation cllaracteristics(ROC) curve is used to judge the diagnostic value of each indicator. Results:There were no significant differences in gender, gestational ages, body weights at birth, ages at NICU of the premature infants between two groups (P>0.05).There were significant differences in the urinary NGAL levels of the premature infants between two groups at different time points (F=62.710, P<0.01);the urinary NGAL level was increased at 24 h after birth, reached the highest peak at 72 h afger birth, and decreased from 72 h after birth.The urinary NGAL levels of the premature infants in AKI group were higher than those in non-AKI group at 24, 48, 72 and 120 h after birth (P<0.05).There were statistically significant differences in the Scr levels of the pretmature infants between two groups at different time points (F=27.332, P<0.05).The Scr levels of the premature infants in AKI group were higher than those in non-AKI group at 48,72 and 120 h after birth (P<0.05). The area under ROC curve (AUC) of urinary NGAL level at 24 after birth was significantly greater than that of Scr level (P<0.01).When the cutoff value of urinary NGAL level was 6.95 ng·dL^-1,the sensitivity and specificity of urinary NGAL level in diagnosis of AKI were 0.900 and 0.836, respectively. Conclusion:The level of urinary NGAL can effectively predict the AKI in the premature infants.

Key words: acute renal injury, premature infants neutrophil gelatinase-associated lipocalin, creatinine, enzyme-linked immunosorbent assay