Urinary Neutrophil Gelatinase-Associated Lipocalin Concentration: A Baseline Study for Establishing Reference Ranges in Preterm Neonates

Abstract Background: Acute kidney injury (AKI) is common in preterm neonates and is associated with morbidity and mortality. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is a promising biomarker for early AKI detection, but its clinical utility is hindered by a lack of normative reference ranges in preterm infants. Objective: To characterize baseline uNGAL concentrations during the first postnatal week in preterm neonates without AKI and evaluate associations with gestational age (GA), birth weight (BW), and sex. Methods: Retrospective cohort study of 100 neonates <32 weeks’ gestation without AKI, NEC, sepsis, or UTI. uNGAL and uNGAL/uCr ratios were measured and analyzed by GA, BW, and sex. Results: uNGAL and uNGAL/uCr levels decreased with increasing GA and BW (p<0.001). Females had higher uNGAL levels than males (p=0.007) Conclusions: Baseline uNGAL varies with GA, BW, and sex in preterm neonates. Development of age-specific reference ranges would enhance the diagnostic utility of uNGAL in neonatal AKI.