title: Application of an optimized flow cytometry-based quantification of Platelet Activation (PACT): Monitoring platelet activation in platelet concentrates.
abstract: BACKGROUND
  Previous studies have shown that flow cytometry is a reliable test to quantify platelet function in stored platelet concentrates (PC). It is thought that flow cytometry is laborious and hence expensive. We have optimized the flow cytometry-based quantification of agonist induced platelet activation (PACT) to a labor, time and more cost-efficient test. Currently the quality of PCs is only monitored by visual inspection, because available assays are unreliable or too laborious for use in a clinical transfusion laboratory. Therefore, the PACT was applied to monitor PC activation during storage.
  
  
  METHODS
  The optimized PACT was used to monitor 5 PCs during 10 days of storage. In brief, optimized PACT uses a ready-to-use reaction mix, which is stable at -20°C. When needed, a test strip is thawed and platelet activation is initiated by mixing PC with PACT. PACT was based on the following agonists: adenosine diphosphate (ADP), collagen-related peptide (CRP) and thrombin receptor-activating peptide (TRAP-6). Platelet activation was measured as P-selectin expression. Light transmission aggregometry (LTA) was performed as a reference.
  
  
  RESULTS
  Both PACT and LTA showed platelet function decline during 10-day storage after stimulation with ADP and collagen/CRP; furthermore, PACT showed decreasing TRAP-induced activation. Major differences between the two tests are that PACT is able to measure the status of platelets in the absence of agonists, and it can differentiate between the number of activated platelets and the amount of activation, whereas LTA only measures aggregation in response to an agonist. Also, PACT is more time-efficient compared to LTA and allows high-throughput analysis.
  
  
  CONCLUSIONS
  PACT is an optimized platelet function test that can be used to monitor the activation of PCs. PACT has the same accuracy as LTA with regard to monitoring PCs, but it is superior to both LTA and conventional flow cytometry based tests with regard to labor-, time- and cost efficiency.
authors.affiliation: Department of Anesthesiology and Pain Therapy, Maastricht University Medical Center, Maastricht, the Netherlands.|Synapse Research Institute, Maastricht, the Netherlands.
authors.forename: Cécile H
authors.identifier: http://orcid.org/0000-0002-8010-8091
authors.initials: CH
authors.lastname: Kicken
authors.affiliation: Synapse Research Institute, Maastricht, the Netherlands.|Department of Biochemistry, Cardiovascular Research Institute, Maastricht University, Maastricht, the Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: Roest
authors.affiliation: Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Yvonne M C
authors.initials: YM
authors.lastname: Henskens
authors.affiliation: Synapse Research Institute, Maastricht, the Netherlands.|Department of Biochemistry, Cardiovascular Research Institute, Maastricht University, Maastricht, the Netherlands.
authors.forename: Bas
authors.initials: B
authors.lastname: de Laat
authors.affiliation: Synapse Research Institute, Maastricht, the Netherlands.|Department of Biochemistry, Cardiovascular Research Institute, Maastricht University, Maastricht, the Netherlands.
authors.forename: Dana
authors.initials: D
authors.lastname: Huskens
mesh_terms: D001792:Blood Platelets / Q000378:metabolism*; D001793:Blood Preservation; D005434:Flow Cytometry / Q000379:methods* / Q000592:standards*; D006801:Humans; D015539:Platelet Activation; D010974:Platelet Aggregation; D010979:Platelet Function Tests / Q000295:instrumentation* / Q000379:methods*