Serum neutrophil gelatinase-associated lipocalin for predicting anemia of inflammation in children with urinary tract infection

Anemia of inflammation (IA), the second most common cause of childhood anemia, results from macrophage iron sequestration and impaired erythropoiesis. Neutrophil gelatinase-associated lipocalin (NGAL) plays an important role in innate microbial immunity through its influence on intracellular iron homeostasis and inhibition of erythropoiesis. The predictive value of NGAL in IA was assessed in 74 children (age 6.30 ±3.64 months) with the first episode of urinary tract infection (UTI). Anemia of inflammation was found in 50% of children, including those with non-febrile UTI, and delayed onset of anemia was observed in 20% of children. There were no differences in NGAL levels between the anemic and non-anemic children, and no correlations between NGAL and hemoglobin (HGB) levels and red blood cell (RBC) count. In multivariate logistic regression analysis elevated C-reactive protein (CRP) was only independently associated with the presence of anemia in children with UTI [OR (95% CI): 1.128 (1.005-1.265), p = 0.040]. In stepwise multiple analysis age independently correlated with RBC (β = 0.051, p = 0.001), while CRP independently correlated with HGB (β = –0.037, p = 0.027) and RBC (β = –0.022, p = 0.014). ROC analysis demonstrated better diagnostic profiles for CRP, procalcitonin (PCT) and fever duration for predicting the risk of IA than NGAL (AUC: 0.690, 0.669, 0.678 vs. 0.638, respectively). Despite the increase in HGB levels after 4-5 weeks from the onset of UTI, HGB values were still significantly lower in the anemic than in non-anemic children. NGAL was not useful for predicting IA in UTI, since its diagnostic value was inferior to conventional inflammatory markers.