Factors limiting usefulness of serum and urinary NGAL as a marker of acute kidney injury in preterm newborns.

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) is postulated to be a highly sensitive and specific marker of acute kidney injury (AKI). The aim of this study was to assess the factors affecting serum and urine total NGAL in preterm newborns, limiting the role of this new potential marker of AKI. METHODS: Serum and urinary total NGAL concentrations were determined in 57 preterm infants admitted to the Neonatal Intensive Care Unit in the following points of time: first week of life, between 8 and 14 days of life, and after the fourth week of life. Patients' clinical conditions were evaluated based on NTISS (Neonatal Therapeutic Intervention Scoring System). Two gestational age subgroups were distinguished: ≤29 and 30 to 35 weeks of gestation. We sought correlation between total NGAL values and gestational age, birth weight, Apgar score and severity of clinical condition, with particular interest in inflammatory status. RESULTS: Serum and urinary total NGAL concentration correlated with inflammatory markers, such as CRP and procalcitonin, as well as with NTISS values. Birth weight and gestational age influence urinary NGAL (uNGAL) values in the first two weeks of life. In AKI (N = 8) patients uNGAL values were significantly higher than in non-AKI newborns. CONCLUSIONS: We conclude that inflammatory status and prematurity limits the specificity of total NGAL measurement as a marker of AKI.

Serum and urinary NGAL in septic newborns.

Neutrophil gelatinase-associated lipocalin (NGAL) is postulated to be a potentially new and highly specific/sensitive marker of acute kidney injury (AKI). The aim of this study was to assess the impact of inflammation on serum and urine NGAL in newborns that were treated due to infection. We determined serum and urine NGAL concentrations in 73 infants (51 with sepsis; 22 with severe sepsis) admitted to the Intensive Care Unit in the first month of life, for three consecutive days during the course of treatment for infection. 29 neonates without infection served as the control group. Septic patients, in particular, severe sepsis patients, had increased serum and urinary NGAL levels in the three subsequent days of observation. Five septic patients who developed AKI had elevated serum and urinary NGAL values to a similar extent as septic neonates without AKI. A strong correlation was found between the concentration of serum and urinary NGAL and inflammatory markers, such as CRP and procalcitonin. Serum and urinary NGAL levels were also significantly associated with NTISS (neonatal therapeutic intervention scoring system) values. We conclude that increased serum and urinary NGAL values are not solely a marker of AKI, and more accurately reflect the severity of inflammatory status.