Mid-stream vs. first-voided urine collection by using automated analyzers for particle examination in healthy subjects: an Italian multicenter study.

BACKGROUND: In analogy with other areas of laboratory diagnostics, the pre-analytical phase is the leading source of variability also in urinalysis. We carried out a multicentric study for comparing results obtained from first-voided and mid-stream urine samples. METHODS: Each of the six hospital-based clinical laboratories participating to this study recruited 50 healthy subjects among laboratory staff and/or their relatives. Two consecutive samples of the first morning micturition were collected by vacuum system, the first from the first-void and the second from the mid-stream. Routine urinalysis was performed using dip-stick automated analyzers for chemical examination and automated analyzers for formed particle examination (Sysmex UF-100, Sysmex UF-1000i and Iris iQ-200). RESULTS: Counts of epithelial cells (EC), erythrocytes (ERY) and leukocytes (LEU) but not for cylinders (CAS) were significantly higher in the first-voided samples. A significantly higher count of EC, ERY and LEU was also observed between females and males in first-voided samples, whereas no significant difference could be found in mid-stream samples. Health related analyzer specific upper reference limits (URL) were CAS≤1, EC≤5, ERY≤19, Leu≤13 for UF-100; CAS≤1, EC≤4, ERY≤15, Leu≤11 for UF-1000i; CAS≤1, EC≤4, ERY≤18, Leu≤10 for iQ200. The overall prevalence of subjects with cellular elements count exceeding URL was also higher in first-voided than in mid-stream samples. CONCLUSIONS: Mid-stream urine was confirmed as the most appropriate sample, since the presence of contaminating elements, such as bacteria, analytes and formed particles are minimized.

Urine particle evaluation: a comparison between the UF-1000i and quantitative microscopy.

BACKGROUND: The study of urine particles plays a key role in the diagnosis of kidney diseases. In this study, the authors evaluated the correlation between the UF-1000i and quantitative manual microscopy. METHODS: A total of 214 untreated urine samples were studied using the Sysmex UF-1000i and compared with results obtained from quantitative manual microscopy using the Fuchs-Rosenthal counting chamber. RESULTS: Using Pearson statistics, we observed satisfactory correlation between the UF-1000i and quantitative microscopy: for red blood cells (RBCs) r was 0.98, for white blood cells (WBCs) r was 1.00, for epithelial cells (EC) r was 0.96, and for casts r was 0.69. Using linear regression statistics, we also observed satisfactory correlation between the UF-1000i and quantitative microscopy: for RBCs R(2) was 0.95, for WBCs R(2) was 0.99, for EC R(2) was 0.92, and for casts R(2) was 0.48. CONCLUSIONS: In our experience, automated urine particle analysis performed using the Sysmex UF-1000i analyzer is sufficiently precise and improves the workflow in a routine laboratory. Precision was satisfactory and concordance with the reference method is good for RBC, WBC and EC; for casts microscopic observation is required for flagged samples to discriminate hyaline from pathologic casts.

Gender's equality in evaluation of urine particles: Results of a multicenter study of the Italian Urinalysis Group.

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.

Pediatric reference values for urine particle quantification by using automated flow cytometer: results of a multicenter study of Italian urinalysis group.

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.

Cutoff values for bacteria and leukocytes for urine flow cytometer Sysmex UF-1000i in urinary tract infections.

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 x 10(5) CFU/mL, 546 positive samples (37%) were observed. If compared with 10 x 10(5) CFU/mL, the cutoff values obtained were 125 bacteria/microL and 40 leukocytes/ microL, 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/microL should be adopted. The cutoff value for bacteria should be 125/microL for those clinical conditions in which 10 x 10(5) CFU/mL indicates a positivity.