Evaluation of Five Automated Urine Analyzers as Screening Instruments for Enhancing Diagnostic Efficiency in Urinary Tract Infection

Abstract

Background: Although urine culture is considered a reference standard for the diagnosis ofurinary tract infection (UTI), it is time-consuming, labor-intensive, and expensive. Here, weevaluated the performance of five recent automated urine analyzers for UTI diagnosis. Methods: For the 510 specimens analyzed, the criterion for ‘significant bacteriuria’ wasdefined as ≥ 104 CFU/mL in the inoculated plate for all specimens or ≥ 103 CFU/mL forspecimens from patients using a Foley catheter or with urinary symptoms. Sensitivity,specificity, positive predictive value (PPV), and negative predictive value (NPV) of UTI wereanalyzed using indicators individually, in different combinations, or with various cut-offvalues. Results: Seventy-one specimens (13.9%) exhibited ‘significant bacteriuria’. In the receiveroperating characteristics curve analysis, UF-5000 (Sysmex Corp., Japan) showed the highestarea under the curve values for both males and females (0.876 and 0.846, respectively). The PPVs for specimens from males with all indicators positive increased up to 100% afteradjusting the cut-off values. NPVs for specimens with all indicators negative were 94.3%–98.2% in males and 78.1%–93.8% in females after adjusting the cut-off values. Conclusion: As a rapid and accurate diagnostic tool, urine sediment analyzers can bevaluable for UTI diagnosis by reducing unnecessary culture and can help cliniciansdetermine a treatment plan.