Assessment of platelet function in healthy sedated cats using three whole blood platelet function tests

Abstract

Abstract. The objectives of this study were to establish feline references intervals for 3 commercial whole blood platelet function test analyzer systems: Multiplate analyzer (MP; Roche Diagnostics International Ltd., Rotkreuz, Switzerland), Platelet Function Analyzer-100 (PF: Siemens Canada, Mississauga, Ontario, Canada), and Plateletworks Combo-25 kit (PW; Helena Laboratories, Beaumont, TX). Venipuncture was performed on 55 healthy sedated cats, and platelet aggregation in response to adenosine diphosphate (ADP), collagen (COL), and arachidonic acid (AA; MP only) was assessed using citrated blood. For the MP analyzer, median (95% confidence intervals [CIs]) area under curve (Units) for ADP, COL, and AA agonists were 87 (11-176), 81 (32-129), and 91 (59-129), respectively. For the PF analyzer, median (95% CIs) closure time, using COL-ADP cartridges, was 69 (46-89) sec. For the PW assay, median (95% CIs) percent aggregations for ADP and COL agonists were 71 (18-92) and 49 (9-96), respectively, using impedance hematology analyzer platelet counts, and 94 (25-98) and 68 (14-119), respectively, using flow cytometry hematology analyzer platelet counts. There were low correlations between the PF analyzer (COL-ADP cartridge) and MP analyzer (COL agonist; ρ = 0.11), and between the PF analyzer (COL-ADP cartridge) and PW assay (COL agonist using impedance platelet counts; ρ = 0.14). The PW assay percent aggregations using impedance and flow cytometric platelet counts were correlated for both ADP (ρ = 0.64) and COL (ρ = 0.64) agonists. Platelet function testing using these tests are feasible in cats, but 95% CIs are wide, so single results may be difficult to interpret. Platelet counting by impedance or flow cytometry may be used for the PW assay but are not interchangeable.

Comparison of Multiplate, Platelet Function Analyzer‐200, and Plateletworks in Healthy Dogs Treated with Aspirin and Clopidogrel

“…Results obtained with both hematology counters were similar for PW. Although the manufacturer's recommendations are to use impedance‐based platelet counts, our study shows that it is valid also to use optically based platelet counts in dogs, as has been previously reported in cats …”

“…The principle of this test is to compare platelet counts before and after the addition of an agonist. It has been validated for use in cats . The use of Plateletworks has not yet been reported in dogs.…”

Abnormal platelet activity in dogs and cats – impact and measurement

“…In cats, normal variability may again limit clinical application (Ho et al . ). However, studies in both healthy cats and those with asymptomatic hypertrophic cardiomyopathy have documented clinically detectable reductions in platelet aggregation following clopidogrel treatment (Hamel‐Jolette et al .…”

“…In cats, normal variability of platelet function and inability to detect clinically relevant changes following anti‐platelet therapy currently limits the use of Multiplate analysis, although future studies may further optimise its use in this species (Ho et al . , Ho et al . ). The Multiplate has also been used to detect reduced platelet aggregation induced in vitro by the addition of lipopolysaccharide to replicate sepsis (Ferkau et al .…”

“…• In healthy dogs, Multiplate® analysis was able to detect reduced platelet aggregation following both aspirin and clopidogrel therapy and as such may have clinical utility for monitoring response to therapy (Saati et al 2017). In cats, normal variability of platelet function and inability to detect clinically relevant changes following anti-platelet therapy currently limits the use of Multiplate analysis, although future studies may further optimise its use in this species (Ho et al 2015, Ho et al 2016). • The Multiplate has also been used to detect reduced platelet aggregation induced in vitro by the addition of lipopolysaccharide to replicate sepsis (Ferkau et al 2013, Li & Chan 2016).…”