<p>Haematology instruments using optical and fluorescence techniques have improved the platelet count in domestic animals. There are still some difficulties present, especially when counting cat thrombocytes due to their ability to aggregate and the occurrence of large platelets.</p><p>The objective of this study was to evaluate and compare the platelet count, mean platelet volume and platelet crit in dogs, horses and cats on Advia 2120 and Sysmex XT-2000iV.</p><p>Fresh blood samples from 64 dogs, 40 horses and 39 cats with various medical conditions were analysed on both instruments. Manual blood smears of all feline samples were scrutiniously analysed to evaluate the aggregation warning flag from Advia.</p><p>There was good agreement between the instruments for the optical platelet count in dogs and cats. Slightly higher values were reported from Advia. Samples from horses presented poor correlations for all studied parameters. Platelet clumps appeared in 70% of the 37 scrutinized feline blood smears, while 46% of the samples generated aggregation warning flags from the Advia instrument.</p><p>Advia and Sysmex showed good agreement for platelet counts in blood from dogs and cats. Mean platelet volume and platelet crit need further evaluation before conclusions can be made concerning their clinical relevance. The sensitivity of the platelet aggregation warning flag from the Advia instument needs further elevation.</p>

Haematology instruments using optical and fluorescence techniques have improved the platelet count in domestic animals. There are still some difficulties present, especially when counting cat thrombocytes due to their ability to aggregate and the occurrence of large platelets. The objective of this study was to evaluate and compare the platelet count, mean platelet volume and platelet crit in dogs, horses and cats on Advia 2120 and Sysmex XT-2000iV. Fresh blood samples from 64 dogs, 40 horses and 39 cats with various medical conditions were analysed on both instruments. Manual blood smears of all feline samples were scrutiniously analysed to evaluate the aggregation warning flag from Advia. There was good agreement between the instruments for the optical platelet count in dogs and cats. Slightly higher values were reported from Advia. Samples from horses presented poor correlations for all studied parameters. Platelet clumps appeared in 70% of the 37 scrutinized feline blood smears, while 46% of the samples generated aggregation warning flags from the Advia instrument. Advia and Sysmex showed good agreement for platelet counts in blood from dogs and cats. Mean platelet volume and platelet crit need further evaluation before conclusions can be made concerning their clinical relevance. The sensitivity of the platelet aggregation warning flag from the Advia instument needs further elevation.