Improving the efficiency and efficacy of pre-analytical and analytical work-flow of urine cultures with urinary flow cytometry.

Quantitative urine culture is one of the most frequently requested tests in microbiology laboratories. An automated system for screening purposes is strongly needed to save technical staff time and obtain rapid results. Our study investigated 1.047 urine samples collected from inpatients and outpatients with a commercial vacutainer system (Becton Dickinson, Milan, Italy) and compared a second-generation flow cytometry (Sysmex UF100, Dasit, Cornaredo, Italy) with standard urine culture tested on agar plated by means of 10 microliter loop. The specimens were screened and cultured on receipt. The results obtained with Sysmex UF-100 are very interesting, especially if this analyzer is used as a screening method for negative urine samples, and comparable to data obtained from culture examination. In fact, considering together bacteria and leukocyte count (> 4500 bacteria and/or > 50 leukocytes/microL) we obtained a negative predictive value of 99.5% in comparison with the standard culture method. The classical culture method needs 24 hours for a result, whereas the Sysmex UF-100 analyzer gives results in a few minutes, thus reducing the microbiology turn around time (TAT) with obvious benefits for patients and physicians.