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Rev Esp Quimioter 2018; January 29

URISCAM project: Multicenter evaluation of the UF-Series cytometer in the urinary tract infections screening

MARÍA DEL MONTE JARABO, MARÍA ÁNGELES ASENCIO, RAFAEL CARRANZA, ÓSCAR HERRÁEZ, MARÍA HUERTAS, ÁNGEL ARIAS-ARIAS, OLGA REDONDO, MARÍA ÁNGELES GALÁN, MARÍA SOLEDAD ILLESCAS, PILAR ZAMARRÓN, SONIA SOLÍS, SILVIA JIMÉNEZ-ALVAREZ

Introduction. Urine culture, the gold standard to confirm the presence of urinary tract infection (UTI), is the most requested assay in the microbiology department. Our objective was to determine the diagnostic yield of the UF-Series cytometer as a screening method for UTI.
Material and methods. All the urine samples sent to the six Microbiology Laboratories participating in a period of 5 working days were analyzed. We collected demographic variables, apart from those variables related to urine samples: source and sample type (midstream, catheterized or nephrostomy urines), collection with/without boric acid, cytometer parameters (leukocyturia, bacteriuria, bacteria morphology and epithelial cells) and urine culture results. ROC curves were plotted to determine predictive capacity of the cytometer.
Results. A sample of 2,468 patients with average age of 53 years were processed (ratio women:men 2:1). Urine culture detected 23% of positive urine samples. The predictor variables of UTI were: morphology of bacilli, bacteriuria ≥21 bacteria/µL, age ≥65 years, samples collected in the emergency service and hospitalization and preserving conditions. With 21 bacteria/µL as a cut-off point, we obtained a sensitivity of 93.3% and 94.5% negative predictive value, then reducing the samples to be cultured by 28.9% with 1.6% false negatives.
Conclusions. We consider that the UF-Series is a valid and accurate tool for the detection of UTI. Therefore, it could be used as screening method in the clinical practice prior to the urine culture, reducing culture requirement by approximately 30%, with a low false negative rate.

Rev Esp Quimioter 2017; Jan 29 [Texto completo PDF]