title: Evaluation of platelet aggregometry in dogs using the Multiplate platelet analyzer: impact of anticoagulant choice and assay duration.
abstract: OBJECTIVE
  To investigate the performance of the Multiplate platelet function analyzer with regards to: (1) the use of 3 different anticoagulants (ie, citrate, hirudin, and heparin) and (2) the evaluation of optimal assay time.
  
  
  METHODS
  Prospective observational in vitro study.
  
  
  METHODS
  University veterinary teaching hospital.
  
  
  METHODS
  Twenty clinically healthy dogs and 3 ill dogs.
  
  
  METHODS
  None.
  
  
  RESULTS
  A total of 184 analyses were performed with duplicate measurements in each test cell and results are reported as mean of the 2 measurements. Analyses were performed on blood samples from 20 dogs collected in citrate, hirudin, or heparin. A total of 4 analyses were performed on every blood sample using adenosine diphosphate, collagen, and arachidonic acid as agonists as well as a control with 0.9% sodium chloride (buffer). Aggregation in hirudin samples was significantly increased compared with heparin at all analysis times except at 6 minutes when using ADP as agonist; however, hirudin samples also demonstrated significant aggregation in the buffer control, compared to both citrate and heparin. Citrated samples yielded significantly lower aggregation compared with both hirudin- and heparin-stabilized samples at 6 and 12 minutes when ADP and collagen were used as agonists, and at most analysis times with arachidonic acid. The assay performed best at shorter analyses times, whereas longer analyses times yielded larger variation in data.
  
  
  CONCLUSIONS
  There was a good aggregation response and acceptable analytical variation in both heparin- and hirudin-anticoagulated samples with all tested agonist at the concentrations recommended by the manufacturer. The results suggest that heparin may be superior as anticoagulant for Multiplate analyses in dogs and that short analyses times are preferable. Spontaneous platelet autoaggregation in hirudin samples warrants careful evaluation of results using this anticoagulant, especially at longer test times. The use of citrate is discouraged for Multiplate analyses in dogs due to a weak aggregation response.
authors.affiliation: Department of Small Animal Clinical Sciences, Faculty of Life Sciences, University of Copenhagen, Denmark. clara@life.ku.dk
authors.forename: Clara B
authors.initials: CB
authors.lastname: Marschner
authors.forename: Annemarie T
authors.initials: AT
authors.lastname: Kristensen
authors.forename: Eva H
authors.initials: EH
authors.lastname: Spodsberg
authors.forename: Bo
authors.initials: B
authors.lastname: Wiinberg
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000494:pharmacology; D019343:Citric Acid / Q000494:pharmacology*; D004285:Dogs; D005260:Female; D006493:Heparin / Q000494:pharmacology*; D006629:Hirudins / Q000494:pharmacology*; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D010979:Platelet Function Tests / Q000295:instrumentation / Q000662:veterinary*; D013997:Time Factors
chemical_list: D000925:Anticoagulants; D006629:Hirudins; D019343:Citric Acid; D006493:Heparin