• Fabio Manoni, Lucia Fornasiero, Mauro Ercolin, Agostino Tinello, Melissa Ferrian, Paolo Hoffer, Sara Valverde, and Gianluca Gessoni.
• Service of Laboratory Medicine, Civil Hospital, 35043 Monselice, Padua, Italy.
• Diagn. Microbiol. Infect. Dis. 2009 Oct 1; 65 (2): 103-7.

AbstractBecause urinary tract infections (UTIs) are a quite common disease, the gold standard for diagnosing UTIs is still bacterial culture, although a large percentage of samples are negative: unnecessary cultures can be reduced by means of an effective screening test. The analytic performance of a new urine cytometer, the UF-1000i, has been tested on 1463 urine samples submitted to our laboratory for culture. Bacteria and leukocyte counts have been compared by means of the UF-1000i with colony-forming unit (CFU) quantification on citrate lactose electrolytes deficient agar to assess the best cutoff values. By using quantitative cultures and considering as positive a sample with 10 x 10(5) CFU/mL, 546 positive samples (37%) were observed. If compared with 10 x 10(5) CFU/mL, the cutoff values obtained were 125 bacteria/microL and 40 leukocytes/ microL, respectively. Analytic parameters such as sensitivity, specificity, positive predictive value, negative predictive value, and correctly classified incidence were satisfactory. Based on the results obtained in this study, when using the UF-1000i analyzer for a screening test for UTI, a cutoff value of 40 white blood cells/microL should be adopted. The cutoff value for bacteria should be 125/microL for those clinical conditions in which 10 x 10(5) CFU/mL indicates a positivity.

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