title: Using the Platelet Function Analyzer-100 for monitoring aspirin therapy.
abstract: BACKGROUND
  The aim of the study was to evaluate the test characteristics of the Platelet Function Analyzer-100 (PFA-100) in patients treated with aspirin.
  
  
  RESULTS
  The study consisted of two sub-studies. In study 1, 10 patients with ischemic heart disease (IHD) and 10 controls had platelet function assessed by optical platelet aggregation and the PFA-100 method in two 5-week periods. Patients with IHD were treated with aspirin 150 mg/day (first 5-week period), and 300 mg/day (second 5-week period), whereas the controls only received aspirin (150 mg/day) during the second 5-week period. From the results of study 1, we found that a cut-off value for the PFA-100 collagen/epinephrine cartridge <165 s identified patients not taking aspirin (sensitivity 0.91, specificity 1.00). A good agreement between the PFA-100 method and optical platelet aggregation was found. Within-subject variation for the PFA-100 collagen/epinephrine cartridge was +/-28%, as compared to +/-17% for the optical platelet aggregation. Study 2 included 298 aspirin treated patients who were admitted with symptoms suggestive of an acute myocardial infarction. Platelet function was assessed in duplicate by the PFA-100 collagen/epinephrine cartridge, and a 95% Limit of Agreement interval at [-65%, 65%] indicated a limited precision.
  
  
  CONCLUSIONS
  We defined a cut-off value below which patients not taking aspirin can be identified. However, due to imprecision of the PFA-100 method repeated duplicate assessment of the collagen/epinephrine Closure Time is recommended.
authors.affiliation: Department of Cardiology, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense C, Denmark. tina.poulsen@ouh.fyns-amt.dk
authors.forename: Tina Svenstrup
authors.initials: TS
authors.lastname: Poulsen
authors.forename: Hans
authors.initials: H
authors.lastname: Mickley
authors.forename: Lars
authors.initials: L
authors.lastname: Korsholm
authors.forename: Peter Bjørn
authors.initials: PB
authors.lastname: Licht
authors.forename: Torben
authors.initials: T
authors.lastname: Haghfelt
authors.forename: Bo
authors.initials: B
authors.lastname: Jørgensen
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D001241:Aspirin / Q000008:administration & dosage / Q000627:therapeutic use*; D016022:Case-Control Studies; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood / Q000188:drug therapy; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D010979:Platelet Function Tests / Q000295:instrumentation* / Q000706:statistics & numerical data; D015203:Reproducibility of Results
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin