[Modifying cutoff values of the UF 1000i(®) automated urine analyzer to predict urinary tract infection]

The fundamental advantage of using automated urine analyzers lies in the current grouping of laboratories as technical divisions. The UF1000i(®) Biomérieux is a 2(nd) generation automated urine analyzer which uses fluorescence flow cytometry to count the particles and bacteria present in urine. It also provides a prediction indicator for the urinary tract infection, based on the leukocyte and bacteria count. The indicator is an alarm (UTI) which triggers according to the cut off values set by the supplier (bacteria count (B): 100000 arbitrary units (AU)/mL, and leukocyte count (L): 25000/mL). Different cut off values of bacteria and leukocytes were evaluated to give the best discrimination, compared with conventional cytobacteriological examination based on the REMIC recommendations of 2010. Our study highlighted two cut off pairs with distinctive performances: L = 15000/mL and B = 100000 AU/mL ; L = 15000/mL and B = 150000 AU/mL. For these cut off values, the negative predictive values is respectively 1 and 0.99. Thus, UF 1000i gives a fairly good indicator for the probable absence of urinary tract infection.