Urinary neutrophil gelatinase-associated lipocalin predicts ICU admission diagnosis: A Prospective Cohort Study

Background: Acute kidney injury (AKI) is most commonly caused by tubular injury and associated with a wide variety of critical illnesses. It is well-known that urinary biomarkers can lead to the early identification of AKI. However, the ability of urinary biomarkers to distinguish between different types of critical illness has been less studied. Methods: In this prospective cohort study, urinary neutrophil gelatinase-associated lipocalin (uNGAL) was measured in 107 patients consecutively admitted to the ICUs in our tertiary medical center. uNGAL samples were collected within 3 to 6 hours of admission to an ICU and measured by ELISA. All data were analyzed using the R statistical software, and univariate analysis was used to determine the correlations of uNGAL levels with AKI stage, admission diagnoses, and ICU course. Results: uNGAL level increased an average of 24 (10-59) fold in ICU patients with AKI and demonstrated a significant correlation with the different AKI stages. uNGAL predicted the need for kidney replacement therapy (KRT) with values increased more than 15-fold (p<0.05) in patients needing KRT and remained a useful tool to predict AKI in ICU patients with a urinary tract infection. uNGAL level was correlated with certain ICU admitting diagnoses whereby uNGAL levels were lower in ICU patients with cardiogenic shock, compared to other admission diagnoses. (β: -1.92, p< 0.05). Conclusions: uNGAL can be used as an early predictor of AKI and its severity in patients admitted to the ICU including the need for KRT. uNGAL may also help in distinguishing patients with cardiogenic shock from those with other critical illnesses and identifying those at risk for poor outcomes irrespective of the presence of AKI.