Urine neutrophil gelatinase-associated lipocalin and other biomarkers in infants with urinary tract infection and in febrile controls

Background Urine biomarkers are commonly used in the evaluation of acute kidney injury, and are gaining attention as tools for studying urinary tract infections (UTIs). We analyzed neutrophil gelatinase-associated lipocalin (NGAL) and seven other urine biomarkers to evaluate their usefulness in the diagnosis of UTI in infants. Methods Eight urine biomarkers were analyzed in 108 infants with UTI. Controls were 64 febrile children without UTI and 13 healthy children. Logistic regression and construction of receiver operating characteristic (ROC) curves were performed for UTI patients versus febrile controls for all biomarkers. Results The best biomarkers to differentiate between UTI and febrile controls were NGAL and interleukin 8 (IL8). Urine NGAL in absolute concentration and adjusted for creatinine had a sensitivity of 93% and 96% and a specificity of 95% and 100% for diagnosing UTI, with a cut-off concentration of 38 ng/mL and 233 ng/mg respectively. Conclusions Urine biomarkers, particularly NGAL, can aid in the diagnosis of UTI among febrile infants. The results suggest that in infants with fever and high NGAL, UTI is most likely, whereas in infants with fever and low NGAL, other causes of fever should be looked for.