Clinical significance of novel biomarker NGAL in early diagnosis of acute renal injury

The present study investigated the clinical significance of the novel biomarker neutrophil gelatinase-associated lipocalin (NGAL) for the early diagnosis of acute renal injury (AKI). Thirty-eight critically ill patients with acute renal injury treated at Zhengzhou No. 7 People's Hospital between December 2015 and November 2016 served as the AKI group (observation group). At the same time, 38 critically ill patients without acute renal injury were also selected as the non-AKI group (control group). Serum NGAL and creatinine (SCr) levels were measured by enzyme-linked immunosorbent assay (ELISA) at 2, 8, 12 and 24 h post-operation, whereas particle-enhanced turbidimetric immunoassay (PETIA) was used to quantify the levels of cysteine protease inhibitor cystatin C (CysC) in serum at 2, 8, 12 and 24 h post-operation. The correlations between indicators were also analyzed, with ROC curves used to evaluate the diagnostic values of NGAL, SCr and CysC in AKI. No significant differences in SCr levels were found between the two groups at different time-points after operation (P>0.05), but NGAL and CysC levels in the observation group were significantly higher than in the control group (P<0.05). Pearson correlation coefficient analysis showed NGAL and CysC were positively correlated with Scr levels. For NGAL in early diagnosis, the area under the AKI curve was 0.904, the sensitivity was 90.2% and the specificity was 89.5%; for CysC in early diagnosis, the area under the AKI curve was 0.806, the sensitivity was 79.2% and the specificity was 78.5%; for SCr in early diagnosis, the area under the AKI curve was 0.634, the sensitivity was 64.2% and the specificity was 62.5%. Therefore, NGAL demonstrated a satisfactory early predictive value for AKI and can be used as a biomarker for early AKI diagnosis.