Serum and Urine neutrophil gelatinase-associated lipocalin in children with urinary tract infection Abdelrahman Fathi Mohamed Elsadek ,Ahmed Galal Siam, Ahmed Mohamed Elsadek , Ezzat Kamel Amin Zagazig University Medical Journal Accepted Manuscript, Available Online from 13 October 2020 Background: Urinary tract infection (UTI) is the commonest bacterial infection in children . Urine culture is the gold standard for diagnosing UTI, but difficulty in urine collection or improperly collected specimen may lead to false positive results of urine culture . the results of urinalysis, such as the presence of leukocyturia, nitrite and leukocyte esterase are used to diagnose UTI in clinical practice, but low sensitivity and specificity of this analysis is an issue . New data show that serum neutrophil gelatinase-associated lipocalin (s NGAL) and urinary NGAL assay can be used for prediction of urinary tract infection (UTI). Aim of the work: this study aimed to investigate the relation between urine and serum neutrophil gelatinase-associated lipocalin and UTI in infants in Zagazig University hospitals . . Patients and Methods: A case control study carried out in Pediatric nephrology unit, Faculty of Zagazig University Hospitals through a duration of six month starting at august 2018. the study included 48 children between 6 and 12 years divided into three groups arranged as cases with febrile UTI, non-febrile UTI and healthy control. all patient were investigated for s NGAL, u NGAL, c-reactive protein, procalcitonin, white blood cell count, urine analysis, urine culture and pelvis- abdominal ultra sound. also, all patient had full detailed history and full examination .Patient with other infections, manifestations of chronic renal failure, manifestations of liver cell failure, evidence of obstructive nephropathy and with vesicoureteral reflux were excluded. Results: the study showed that, there was significant increase in level of serum NGAL in patients with febrile and non-febrile UTI in comparison to healthy control group with mean sensitivity 100%, specificity 75%, positive predictive value 66.7%, negative predictive value 100% and cutoff of serum NGAL in prediction of presence of febrile UTI in the studied patients is ≥ 140(pg/ml) with area under curve 0.906 .There was significant increase in level of urine NGAL in patients with febrile UTI in comparison to patients with nonfebrile UTI and healthy control group with sensitivity 81.2%, specificity 50%, positive predictive value 76.5%, negative predictive value 57.1% and cutoff of urine NGAL in prediction of presence of febrile UTI in the studied patients is ≥ 129(pg/ml) with area under curve 0.774 . Conclusions: Serum NGAL had sensitivity and specificity in prediction of UTI in studied patients more than urine NGAL..