Automated urinalysis combining physicochemical analysis, on-board centrifugation, and digital imaging in one system: A multicenter performance evaluation of the cobas 6500 urine work area

• Main Authors: Christa M. Cobbaert, Figen Arslan, Imma Caballé Martín, Antoni Alsius Serra, Ester Picó-Plana, Víctor Sánchez-Margalet, Antonio Carmona-Fernández, John Burden, André Ziegler, Walter Bechel
• Format: Article
• Language: English
• Published: Elsevier 2019-11-01
• Series: Practical Laboratory Medicine
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352551718301501

Background: We evaluated the analytical performance of the fully automated cobas® 6500 urine work area and its automated components—cobas u 601 and cobas u 701. Design and methods: The study was conducted at three European centers using un-centrifuged surplus routine urine samples; all measurements were performed within 2 h of sample collection. Precision, sample carry-over, and method comparisons were evaluated per Clinical and Laboratory Standards Institute guidelines. Method comparisons: cobas u 601 versus Urisys 2400 and cobas u 411 urine test strips; and cobas u 701 versus KOVA® visual microscopy and iQ200 analyzer. Operability and functionality were assessed using questionnaires. Results: Precision of the entire cobas 6500 system was within predefined acceptance limits and no significant carry-over was observed. Erythrocytes, leukocytes, nitrites, and protein were in good agreement (≥93%) with cobas u 411 reflectometry. High correlation was shown between the cobas u 701 analyzer and KOVA visual microscopy for red blood cells (RBC; slope, 0.89; Pearson’s r, 0.95) and white blood cells (WBC; slope, 0.96; Pearson’s r, 0.96), demonstrating equivalence of test results. The 97.5% percentile reference values on the cobas u 701 analyzer were 5.3 cells/μL (RBC) and 6.2 cells/μL (WBC). The cobas 6500 system showed good sensitivity for small bacteria (>1 μm) and pathological casts, and the user interface, maintenance wizards, and system design were highly rated by operators. Conclusions: The fully automated workflow, high precision, and high throughput of the cobas 6500 system have the potential to facilitate standardization of urine screening. Keywords: Clinical automation, Automated biology—high-throughput screening, Laboratory management—workflow