Evaluation of the IDEXX ProCyte Dx analyzer for dogs and cats compared to the Siemens ADVIA 2120 and manual differential

Abstract

The ProCyte Dx™ was introduced as an in-house hematology analyzer based on focused flow impedance and flow cytometry. It provides a complete hemogram including a five-part leukocyte differential and reticulocyte count. The aim of the study was to evaluate the ProCyte Dx for dogs and cats. EDTA-anticoagulated blood samples from healthy or diseased dogs (n = 270) and cats (n = 176) were analyzed within 3 to 6 h of sampling. Routine hemogram variables including reticulocytes were compared with reference methods, i.e., the ADVIA 2120, a 200-cell manual differential leukocyte count, and manual reticulocyte counts. Data were analyzed twice (prior to and after dot plot analysis, with the exclusion of samples with invalid separations of cellular populations). Coefficients of variation were <3 % for complete blood cell count and <7 % for differential count, except for eosinophils (cat, 17 %), lymphocytes (cat, 30 %), platelet counts (PLTs; dog, 14 %), and reticulocytes (dog and cat, 16 and 22 %, respectively). Spearman’s rank correlation coefficients (r s) revealed a good to excellent (r s = 0.99–0.80) correlation between both analyzers, except for the mean corpuscular hemoglobin concentration (MCHC; r s = 0.56–0.44), cat reticulocytes (r s = 0.77), and differential count prior to dot plot analysis. Biases were generally close to 0; however, large biases were seen for hemoglobin (HGB), mean corpuscular hemoglobin, MCHC, mean corpuscular volume, PLTs, and differential count prior to dot plot analysis. The majority of variables correlated favorably with the ADVIA 2120. The large biases of HGB and HGB-derived variables were due to the methodology of the ADVIA. Dot plot analysis is an additional tool for quality assurance, and a manual differential count is recommended in case of invalid separation of cellular populations.