Optimized gating and reference ranges of reticulated platelets in dogs for the Sysmex XT-2000iV

BACKGROUND: Canine reticulated platelets (r-PLTs) i.e., juvenile PLTs reflecting thrombopoiesis can be measured automatically with the hematology analyzer Sysmex XT-2000iV using manual gating options. However, the impact of interferences on r-PLT measurements performed with the gates published previously (Pankraz et al., Vet Clin Path 38:30–38, 2009; Gelain et al., High fluorescent platelets fraction in macrothrombocytopenic Norfolk terrier, 2010) is largely unknown. The aim was to compare different published gates for measurement of r-PLTs with the Sysmex XT-2000iV with an own, optimized gate (“Oellers-gate”) and to establish reference intervals (RIs) in > 120 dogs. Data of 362 measurements of diseased and healthy dogs were analyzed retrospectively. Several gates were applied and RIs for r-PLTs and platelet indices were established for pet dogs and a group of 153 healthy Beagles kept under defined housing conditions. Intra-assay precision (CV) was also assessed. RESULTS: In 30/362 samples, interferences consistent with small erythrocytes/reticulocytes were seen in the previously published gates but not in the “Oellers-gate”. Good correlation was found between the different gates (r(s): 0.88–1.00). RIs for the “Pankraz-gate”, the “Gelain-gate”, and the “Oellers-gate” were 0.0–1.2, 0.2–3.7 and 0.2–3.9 % respectively. CVs were ranging between 22 and 41 %. CONCLUSIONS: Optimization of previously published gates minimized interferences of small erythrocytes with r-PLT measurements.