Potential role of neutrophil gelatinase-associated lipocalin in identifying critically ill patients with acute kidney injury stage 2-3 who subsequently require renal replacement therapy.

Delayed initiation of renal replacement therapy (RRT) in critically ill acute kidney injury (AKI) patients results in high mortality while too early RRT causes unnecessary risks of the treatment. Current traditional indications cannot clearly identify the appropriate time for initiating RRT. This prospective cohort study was conducted to determine the accuracy of using plasma neutrophil gelatinase-associated lipocalin (pNGAL) and urine NGAL (uNGAL) in early identifying of the AKI patients who subsequently required RRT. Forty-seven critically ill patients with AKI stage 2-3 who did not reach the traditional indications for RRT were enrolled in this study. The pNGAL, uNGAL, and other parameters were determined in each patient. The primary end point was RRT initiation according to the traditional indications within 3 days. The mean age of the patients was 63.0 ± 18.1 years. pNGAL could predict subsequent RRT requirements with area under ROC 0.813 (P < 0.001, 95%CI 0.66-0.90). The cut-off point of 960 ng/mL provided sensitivity and specificity of 72.2 and 89.6%, respectively, and positive and negative predictive values of 81.25% and 83.8%, respectively. The uNGAL provided slightly lower significance of statistical parameters. The combination of pNGAL level of 960 ng/mL and APACHE II score of 20 improved statistical values. In conclusion, pNGAL is an excellent early biomarker for RRT initiation in critically ill patients with AKI stage 2-3. The pNGAL value of 960 ng/mL, alone or in combination with APACHE II score might be used as the early new indicator for early initiation of RRT in AKI stage 2-3 and this might improve patient survival.