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. Clin Chem Lab Med 2010;48:1107-11.