Clinical laboratory automated urinalysis: comparison among automated microscopy, flow cytometry, two test strips analyzers, and manual microscopic examination of the urine sediments

Urinalysis is one of the habitual clinical laboratory procedures, which implies that one of the largest sample volumes currently requires significant labor to examine microscopic sediments. Different analyzers currently used to perform this task have been compared with the manual microscopic sediment examination. The Atlas Clinitek 10 (Bayer Corporation, Diagnostics Division, Tarrytown, NY) and Urisys 2400 (Hitachi Science Systems Ltd., Ibaraki, Japan) test strips analyzers and two automated urinalysis systems, Sysmex UF-100 (Sysmex Corporation Kobe, Japan) and IRIS iQ200 (International Imaging Remote Systems, Chatsworth, CA), have been considered. We assessed the concordance between the results obtained from 652 freshly collected urine samples for erythrocytes (RBC), leukocytes (WBC), squamous epithelial cells (EC), nitrites/bacteria, and crystals using the methodologies mentioned. A principal components analysis was performed in order to examine the correlation between these parameters. Instrument accuracy was also assessed. The Spearman's statistic (p) showed an adequate agreement between methods for RBC (iQ200=0.473; UF-100=0.439; Atlas=0.525; Urisys=0.539), WBC (iQ200=0.695; UF-100=0.761; Atlas=0.684: Urisys=0.620), and bacteria/nitrites (iQ200=0.538; UF-100=0.647; Atlas=0.532; Urisys=0.561) counts. By applying the Wilcoxon and McNemar tests, a concordance degree was found between 82-99 and 52-95% for the values obtained from the two test strips analyzers considered and from the iQ200 and UF-100 systems, respectively. From these results, we can conclude that both test strips analyzers are similar and, on the other hand, that automated urinalysis is needed to improve precision and the response time; but sometimes manual microscopic revisions are required, mainly when flags, because of crystals, are detected.