Thrombocytopenia in the cavalier King Charles spaniel

Abstract

Blood samples were collected for the determination of platelet counts from 102 cavalier King Charles spaniels which had no history of bleeding disorders. Thrombocytopenia was found in 31 per cent of the samples when the lower reference limit was set at 100 X 109/litre. The platelet count of the males (mean ± SD, 147 X 109/litre ± 15 X 109/litre) was found to be significantly (P<0.05) lower than that of the females (mean ± SD, 202 X 109/litre ± 13 X 109/litre). The platelet counts from a reference group of 16 normal beagles, analysed identically, were not lower than 189 X 109/litre and no significant difference was found between males (mean ± SD, 249 X 109/litre ± 14 X 109/litre) and females (mean ± SD, 282 X 109/litre ± 20 X 109/litre).

Comparison of Manual and Automated Methods for Determining Platelet Counts in Dogs with Macrothrombocytopenia

“…14 Erroneously low platelet counts measured by automated cell counting systems in CKCS with low platelet counts have been described previously in studies using flow cytometer (Cell-Dyn 3500) and other impedance analyzers. 2,4,9 The impedance analyzer b that identifies cells on the basis of the distribution of cell sizes in the sample was the automated system that correlated best with the reference method in this study. However, a marked underestimation at low platelet counts was still seen.…”

“…4,9,10 Manually performed platelet counts are recommended in CKCS with macrothrombocytopenia because automated cell counting systems cannot distinguish enlarged platelets from red blood cells and thus underestimates platelet counts. 2,4,9 Different manual methods are available for determining platelet counts, including evaluation of blood smears and methods using erythrocyte-lysing agents followed by platelet counting in a counting chamber. 4,7,12 Manual methods, however, are time-consuming and dependent of the skill of the operator.…”

“…2,4,9 Different manual methods are available for determining platelet counts, including evaluation of blood smears and methods using erythrocyte-lysing agents followed by platelet counting in a counting chamber. 4,7,12 Manual methods, however, are time-consuming and dependent of the skill of the operator. 7 Furthermore, a rapid evaluation of platelet count is desirable for studies of platelet aggregation, in which fresh blood is essential for reliable results and platelet concentrations must be standardized.…”

“…In the microscope, reduced bright light and lowered condenser were used to make it easier to identify platelets. In the stromatol method, as previously described, 4 20 l of the EDTA-anticoagulated blood was mixed with 380 l stromalytic agent, e before the platelets were counted in a Bürker Türk counting chamber (within 24 hours). A stromatol platelet count was only obtained from 20 dogs (including 2 control dogs).…”

“…4,7,12 In the Unopette method, 20 l of EDTA-anticoagulated blood was mixed with 1.98 ml of a solution containing ammonium oxalate within 4 hours from blood sampling. After erythrocyte hemolysis (minimum 10 minutes but within 3 hours), platelets were counted manually in a Bürker Türk counting chamber 10 minutes after platelet settling as a single assay by 1 of the authors.…”