Evaluation of canine and feline leukocyte differential counts obtained with the scil vCell 5 compared to the Advia 2120 hematology analyzer and a manual method

• Published in: Journal of veterinary diagnostic investigation Vol. 35; no. 6; pp. 679 - 697
• Main Authors: Zelmer, Kim-Lina Charlotte, Moritz, Andreas, Bauer, Natali
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.11.2023
• Subjects: total error; laser flow cytometry; 5-part differential; agreement; method comparison; point-of-care
• DOI: 10.1177/10406387231187899
• ISSN: 1040-6387

The vCell 5 (scil Animal Care), a point-of-care hematology analyzer (POCA), was recently introduced to veterinary laboratories. This laser- and impedance-based analyzer is capable of providing a CBC with 5-part WBC differential count (Diff) along with WBC cytograms and flags serving as interpretation aids for numerical results. We compared the scil POCA-Diff to reference methods (i.e., manual differential count, Advia 2120 hematology analyzer [Siemens]) for canine and feline blood samples and considered WBC cytograms and flags. Total observed error (TEo), calculated from CV and bias%, was compared to total allowable error (TEa). Data were analyzed before and after a review process (exclusion of flagged and samples with invalid cytograms). For both species, correlation was good-to-excellent (rs = 0.81–0.97) between both analyzers for all variables, except for feline monocytes (rs = 0.21–0.63) and canine monocyte% (rs = 0.50). Smallest biases were seen for neutrophils (dog: −5.7 to 0.8%; cat: 1.5–9.4%) with both reference methods. Quality requirements (TEo < TEa) were fulfilled for canine and feline neutrophils (TEo = 5.3–10.6%, TEa = 15%) and eosinophils (TEo = 67.1–83%, TEa = (90)–50%) considering at least one reference method. Our review process led to mildly higher rs-values for most variables. Although not completely satisfactory, the scil POCA provides reliable results in compliance with ASVCP quality goals for canine and feline neutrophils and eosinophils. Analyzer flag and cytogram analysis served as useful tools for QA, indicating the necessity for manual review of blood smears, and contributed to improvement of scil POCA performance.