title: Impact of platelet count on results obtained from multiple electrode platelet aggregometry (Multiplate).
abstract: OBJECTIVE
  Use of potent antiplatelet drugs requires evaluation of platelet function. While platelet function in elective cases is usually assessed in a central laboratory environment, there is also an urgent need for rapid perioperative point-of-care assessment. Recently, multiple electrode platelet aggregometry has been developed and assumed to measure platelet function independent from platelet count. We tested the hypothesis that results of multiple electrode platelet aggregometry are affected by platelet count, in particular if platelet count is below normal range.
  
  
  METHODS
  Whole blood samples from 20 healthy volunteers were prepared containing platelet concentrations of 50,000, 100,000, 150,000, 200,000, and 250,000 microl(-1) while maintaining hematocrit. Platelet aggregation was induced by collagen, thrombin receptor activating peptide 6 (TRAP-6), adenosine-diphoshate (ADP), and arachidonic acid, respectively, and aggregation was measured by multiple electrode platelet aggregometry (Multiplate).
  
  
  RESULTS
  Results of multiple electrode platelet aggregometry significantly decreased in blood samples with platelet count below normal range. Compared to results measured in blood samples with platelet count within normal range, aggregometry results decreased by 18.4 % (p<0.001) and 37.2 % (p<0.001) in blood samples with a platelet count of 100.000 and 50.000 microl(-1), respectively. On the other hand, large interindividual variation has been observed and some blood samples showed normal results even with platelet counts of 50.000 microl(-1).
  
  
  CONCLUSIONS
  The results obtained with Multiplate. Analyzer are influenced by platelet function as well as platelet count thus displaying the overall platelet aggregability within the blood sample rather than platelet function alone.
authors.affiliation: Klinik für Anästhesiologie und Intensivmedizin, Medizinische Hochschule Hannover, Hannover, Germany. hanke.alexander@mh-hannover.de
authors.forename: A A
authors.initials: AA
authors.lastname: Hanke
authors.forename: K
authors.initials: K
authors.lastname: Roberg
authors.forename: E
authors.initials: E
authors.lastname: Monaca
authors.forename: T
authors.initials: T
authors.lastname: Sellmann
authors.forename: C F
authors.initials: CF
authors.lastname: Weber
authors.forename: N
authors.initials: N
authors.lastname: Rahe-Meyer
authors.forename: K
authors.initials: K
authors.lastname: Görlinger
mesh_terms: D019540:Area Under Curve; D005260:Female; D006801:Humans; D008297:Male; D010974:Platelet Aggregation; D010976:Platelet Count; D010979:Platelet Function Tests / Q000295:instrumentation*; D019095:Point-of-Care Systems