Diagnostic accuracy of three automated urine analyzers compared to urine culture

Urine culture is an important diagnosis method of urinary tract infection. However, it is time-consuming and results aren’t available quickly. Automated urine analyzers have been developed to screen urine samples more rapidly. The goal of this study was to compare three automated analyzers to urine culture: the Atellica UAS 800 (Siemens, Munich, Germany), the UF-4000 (Sysmex, Kobe, Japan) and the SediMAX (Menarini, Florence, Italy).
We first validated each analyzer. We analyzed then 318 samples with the three analyzers within 2 hours after sample reception. An urine aliquot was collected before sediment analysis for bacteria culture. Ten microliters of un-centrifuged urine was inoculated on blood agar and CLED agar plates, then they were incubated aerobically at 36°C for 24 h. Bacteria count of each analyzer was compared to urine culture to determine diagnostic accuracy. The result was considered positive when the bacteria growth reached 104 CFU/ml. We also used the results of leukocytes and nitrites results from the strip measurement to improve the accuracy. The abilities of the UF-4000 to distinguish Gram positive (GP) from Gram negative (GN) bacteria, and of the UAS 800 to identify rod and cocci, were determined.