Diagnostic value of flow cytometric urine analysis in urinary tract infections of newborns and infants.

This study aimed to compare the results of flow cytometric urine analysis and urine culture for the rapid diagnosis of urinary tract infections and to determine the leukocyte and bacterial cutoffs that could achieve maximum sensitivity and negative predictive value (NPV) during the newborn and infant periods. This cross-sectional observational study included urine samples submitted for culture from the neonatal intensive care unit and outpatient clinic between April 2019 and December 2021. The urine samples were first inoculated for culture and then analyzed for leukocyte and bacterial counts using a flow cytometric method (Sysmex UF-1000i, Kobe, Japan). Maximum sensitivity and NPV values ​​were determined by examining different bacterial and leukocyte cut-offs with Sysmex UF1000i. A total of 138 urine samples from 103 patients were included in the study. The reasons for urine examinations were prolonged hyperbilirubinemia, sepsis, and insufficient weight gain. Although no association was observed with leukocyte count, a bacterial cut-off of 83.4/µL was identified as the optimal threshold. Diagnostic values, including sensitivity (91.6%), specificity (88.6%), NPV (98.5%), and positive predictive value (PPV) (55%), were satisfactory. Based on current data, we suggest that the Sysmex UF-1000i is a valuable screening tool for detecting UTIs in asymptomatic newborns. Integrating this technology into clinical practice could enhance early diagnosis and treatment, ultimately improving neonatal care outcomes.