Application Of Urinary NGAL And Cystatin C In Early Diagnosis And Efficacy Evaluation Of Acute Kidney Injury In Premature Infants

Objective: To investigate the value of urinary neutrophil gelatinase-associated lipocalin(uNGAL)and urinary cystatin C(uCys C)in the early diagnosis of acute kidney injury(AKI)in premature infants and to determine the efficacy.Methods: A prospective study was conducted in 98 premature infants admitted to the Dalian Women and Children Medical Center NICU from November 2018 to October2019.10 cases of AKI and 88 cases of non-AKI were confirmed on the first day of inclusion,3 cases of AKI and 95 cases of non-AKI were confirmed on the seventh day of inclusion.Data collection:gestational age,birth weight,sex and hourly urine volume per kg body weight were collected.Urine samples were collected on the day1,day7 of inclusion and the day of in urine volume decreased significantly(urine output < 1.5m L/(kg·h)),uNGAL and uCys C values were measured by ELISA.Serum creatinine was analysed.Statistical analysis: SPSS 22.0 statistical software was performed.The t test the mann-whitney U test and the chi-square test were used for inter-group comparison.The specificity and sensitivity of uNGAL and uCys C in the early diagnosis of AKI in premature infants were determined by receiver operating characteristic curve(ROC)and area under ROC curve(AUC).To determine the optimal cut-off value,95%CI,positive predictive value and negative predictive value of uNGAL and uCys C in the diagnosis of premature infants with AKI.Results: The uNGAL and uCys C level in AKI group were significantly higher than those in the non-AKI group(P < 0.05).On the day1 and day 7,the sensitivity of uNGAL in diagnosing AKI was 1,and the specificity was 0.659 and 0.695.On day1 and day 7,the sensitivity of uCys C in diagnosing AKI was 0.900 and 1,and the specificity was 0.795 and 0.737.When 98.48 ?g/L was choosed for the optimal cutoff value,both positive predictive value of uNGAL on day1 and day7 were 100% and the negative predictive value on day 1 and day 7 was 65.91% and 62.11%.When 104.62 ?g/L was the optimal cutoff value,the positive predictive value of uNGAL on day 1 and day 7was 90% and 100%,and the negative predictive value on day 1 and day 7 was 75% and69.47%.When 25.19ng/m L was the optimal cutoff value,the positive predictive value of uCys C on day 1 and day 7 was 90% and 66.67% and the negative predictive value on day 1 and day 7 was 80.68% and 78.95%.When 23.16ng/m L was the optimal cutoff value,the positive predictive value of uCys C on day 1 and day 7 was 90% and 100%,and the negative predictive value on day 1 and day 7 was 68.18% and 73.68%separately.Conclusions: uNGAL aund uCys C can be used as biological indicators for the early diagnosis of AKI in premature infants.