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Abstract: Objective: We performed a multicenter study to calculate the upper reference limits (URL) for urine particle quantification in mid-stream samples by using automated urine analyzers. Design & methods: Two laboratories tested 283 subjects using a Sysmex UF-100, two other laboratories tested 313 subjects using Sysmex UF-1000i, whereas two other laboratories tested 267 subjects using Iris IQ®200. Results: The URLs of UF-100 in females and males were 7.8/μL and 6.7/μL for epithelial cells (EC), 11.1/μL and 9.9/μL for red blood cells (RBC), 10.2/μL and 9.7/μL for white blood cells (WBC), and 0.85/μL and 0.87/μL for cylinders (CAST). The URLs of UF-1000i in females and males were 7.6/μL and 7.1/μL for EC, 12.2/μL and 11.1/μL for RBC, 11.9/μL and 11.7/μL for WBC, and 0.88/μL and 0.86/μL for CAST. The URLs of Iris IQ®200 in females and males were 7.8/μL and 6.6/μL for EC, 12.4/μL and 10.1/μL for RBC, 10.9/μL and 9.9/μL for WBC, and 1.1/μL and 1.0/μL for CAST. Conclusion: The URLs obtained in this study were comparable to the lowest values previously reported in the literature. Moreover, no gender-related difference was observed, and analyzer-specific upper reference limits were very similar. [Copyright &y& Elsevier]

Abstract: Objectives: The purpose of this Italian multicenter study was to define pediatric upper reference values for urine particle quantification by using automated flow cytometry. Design and methods: Four hospital-based clinical laboratories participated in this multicenter investigation, which included a total study population of 161 Italian children aged from 1 to 12years. Two laboratories used Sysmex UF-100 and analyzed 86 children, whereas the other two used Sysmex UF-1000i and analyzed 75 subjects. Particle quantification included the analysis of white blood cells (WBC), red blood cells (RBC), squamous epithelial cells (EC), transitional epithelial cells (TC), casts (CAST) and bacteria (BACT). Results: The upper reference values in subjects tested with the Sysmex UF-100 were 9.7WBC/μL, 10.1RBC/μL, 7.5EC/μL, 2.5TC/μL, 0.7CAST/μL and 3090BACT/μL, whereas the upper reference values in subjects tested with the Sysmex UF-1000i were 10.5WBC/μL, 8.3RBC/μL, 7.2EC/μL, 2.9TC/μL, 0.7CAST/μL and 48BACT/μL. No statistically significant differences between genders were found in the value distribution of any of the parameters tested. Similarly, no statistically significant differences were observed between the two urine analyzers, except for BACT. Conclusions: Automated analysis of urine particles appears a suitable means to optimize the workflow of routine urinalysis of children specimens. The upper reference limits for pediatric subjects obtained in this study were comparable to those previously reported in the literature, with no significant differences between genders and analyzers. [Copyright &y& Elsevier]

Abstract: Because 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 × 105 CFU/mL, 546 positive samples (37%) were observed. If compared with 10 × 105 CFU/mL, the cutoff values obtained were 125 bacteria/μL and 40 leukocytes/ μL, 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/μL should be adopted. The cutoff value for bacteria should be 125/μL for those clinical conditions in which 10 × 105 CFU/mL indicates a positivity. [Copyright &y& Elsevier]

Abstract: Background: Urinary tract infections (UTIs) are usually diagnosed by urine particle detection and urine bacterial culturing, but an empiric treatment is often prescribed before the microbiological results are known. The aim of this study was to assess whether quantification of bacteriuria and leukocyturia could predict the outcome of empiric antibiotic therapy. Methods: By using a Sysmex UF-100 analyser, we performed a case–control study in which bact channel counts (BCCs) and leukocyte (WBC) quantification were compared in urine samples obtained from responsive patients (RPs) and non-responsive patients (NRPs) at diagnosis (t0) and 24h (t24) after the start of empiric antibacterial treatment. Results: BCCs decreased significantly from t0 (median: 30,000 E6/L) to t24 (median: 700 E6/L; p <0.001) in RPs but not in NRPs (median at t0 31,000 E6/L, and 23,000 E6/L at t24; p >0.05). Similarly, WBC counts were reduced in RPs at t24 relative to the initial values (p <0.001) but not in NRPs. A reduction of 70% in the BCC count or 60% in the WBC count of paired samples was useful for discriminating between RPs and NRPs. Conclusions: Our results suggest that quantitative time course analysis of urine BCCs and WBCs can be used to predict the success of first-line empiric treatment for UTIs. [Copyright &y& Elsevier]