Eearly diagnostic value of urinary NGAL in acute kidney injury in critically ill patients

Objective To estimate the predictive value of neutrophil gelatinase-associated lipocalin in urine (uNGAL) for detection of acute kidney injury (AKI) in the intensive care unit (ICU) critically ill patients.Methods A total of 110 patients from the ICU of three general hospitals were enrolled in the study.The patients were adults more than 18 years of age.After admitted to ICU,the patients were continuously observed for 72 hours.According to the RIFLE criteria for diagnosis of AKI,the patients were classified as AKI group (33 cases) or non-AKI (77 cases).According to the sepsis diagnostic criteria,the patients were classified as sepsis (79 cases) or non-sepsis (31 cases).Exclusion criteria of patients were chronic renal insufficiency,malignant tumor,death after admitted to ICU 24 hours.Serum creatinine and uNGAL of the patients were analyzed daily.The difference of uNGAL between sepsis and non-sepsis patients,AKI and non-AKI patients,sepsis non-AKI and sepsis AKI patients was compared.Moreover,the difference of serum creatinine and uNGAL between AKI and non-AKI patients into ICU 24 h was compared,and the sensitivity and specificity of uNGAL and serum creatinine for diagnosis of AKI in the ICU patients were evaluated using ROC curve.Results The uNGAL levels were all significantly different between sepsis and non-septis patients,AKI and non-AKI patients,sepsis concomitant AKI and sepsis without AKI patients.The uNGAL levels were significantly different between AKI and non-AKI patients in ICU for the first 24 h,while the difference of serum creatinine were not significant.The area under receiver operating characteristic (ROC) curve of uNGAL and serum creatinine of patients in ICU for the first 24 h were 0.828 (95％ CI:O.742-0.914) and 0.583 (95％ CI:0.471-0.695),respectively.The cutoff value of uNGAL was 170 ng/ml,and the sensitivity and specificity were 0.778 and 0.784,respectively.The sensitivity was superior to serum creatinine.Conclusions uNGAL was superior to serum creatinine in the diagnosis of AKI,and could be used as a marker of the early diagnosis of AKI. Key words: Neutrophil gelatinase-associated lipocalin (NGAL) ;  Serum creatinine ;  Sepsis ;  Acute kidney injury (AKI);  Sensitivity;  Specificity