Evaluation of the possibility of using urinary neutrophil gelatinase-dependent lipocalin as a predictor of acute kidney injury in intensive care unit patients

Introduction: Due to the increase in the incidence of acute kidney injury (AKI), especially in patients admitted to the intensive care unit (ICU), its occurrence has been studied using biomarkers such as urinary neutrophil gelatinase-dependent lipocalin (uNGAL). However, its clinical utility has not yet been approved. Objectives: This study aimed to investigate the possibility of using uNGAL as a predictor of AKI in patients admitted to the ICU. Patients and Methods: This prospective study was conducted on 32 patients admitted to the ICU who had normal creatinine level at the ICU admission and did not fulfill the RIFLE (risk, injury, failure, loss of kidney function, and end-stage kidney disease) criteria. Initially, creatinine level and the sequential organ failure assessment (SOFA) score were recorded. In the first 24 hours of hospitalization, urine samples were taken from patients to assess uNGAL levels. In the following days, creatinine levels and the day of its rise were recorded. The incidence of AKI was assessed based on the RIFLE criteria, and the relationship between the AKI incidence and the uNGAL level at admission was assessed. Results: The mean (SD) of patients’ age was 63 ± 17 years, and 18 patients (56%) were male. The cause of hospitalization was post-cardiac surgery in 21 patients (66%). The median SOFA score of patients was 2.5 at admission. According to the RIFLE criteria, 47% of patients had kidney problems at different stages. The median length of hospital stay was 13 days, while four patients (13%) died. Range and mean (SD) of uNGAL level at admission in all patients was 46.1 to 172.5 ng/mL and 89.94 ± 30.9 ng/mL, respectively, which was not significantly different between the two sexes and between living and deceased patients. Although the mean of uNGAL increased in patients in the risk and injury stage of the RIFLE criteria compared to normal patients, the difference between them was not significant. The increase in uNGAL was directly related to the increase in SOFA score (Spearman’s rho = 0.360, P = 0.043), while its changes was not significantly related to age or creatinine elevation ratio. Conclusion: The findings of our study showed that, in ICU admitted patients, first-day uNGAL level was not helpful in predicting AKI based on the RIFLE criteria.