Evaluation of the point-of-care hematology analyzer scil vCell 5 for leukocyte differential counts in dogs and cats

Introduction Recently, the novel laser and impedance-based point-of-care hematology analyzer (POCA) scil vCell 5 was introduced providing a complete blood count including a 5-part differential count. White blood cell cytograms and flags are displayed automatically. The objective of the study was to evaluate the accuracy of the leukocyte differential count of the scil POCA for canine and feline specimens with consideration of leukocyte cytograms and flags in comparison to the corresponding reference methods, i.e., the ADVIA 2120 hematology analyzer and a manual 200-cell leukocyte differential count (MDiff).

Methods For the method comparison study, fresh blood samples from healthy and diseased dogs (n=192) and cats (n=159) were analyzed within 6 hours after sampling. Total observed error (TEobs) was calculated from coefficient of variation and bias% and compared to total allowable error (TEa) according to published ASVCP guidelines. Data were analyzed prior and after the validation process (exclusion of samples with flags and abnormal cytograms).

Results For both species, good correlation (rs=0.86–0.91) was seen between both analyzers for neutrophils (NEU), lymphocytes (LYM), and eosinophils (EOS). Correlation between the scil POCA and MDiff was good for NEU, LYM, and feline EOS (rs=0.80–0.86) to fair for canine EOS (rs=0.75). For monocytes (MON), poor correlation between methods was seen (rs=0.21–0.5). Quality requirements (TEobs<TEa) were fulfilled for canine and feline NEU (TEobs=5.3–10.6%, TEa=15%), and EOS (TEobs=67.1–83.0%, TEa=50(–90)%). The validation process led to increased correlation for most of the variables.

Conclusion The scil POCA provides acceptable performance for prevalent leukocyte species with good correlation with reference methods for NEU, LYM, and EOS and compliance with ASVCP quality guidelines for NEU and EOS. Analyzer flags and cytogram analysis serve as useful tools for quality assurance indicating the necessity for manual review of blood smears and contributing to improvement of analytical analyzer performance.

Publication History

Article published online:
14 March 2023