Using the Platelet Function Analyzer-100 for monitoring aspirin therapy

Thromb Res. 2007;120(2):161-72. doi: 10.1016/j.thromres.2006.08.010. Epub 2006 Oct 18.


Introduction: The aim of the study was to evaluate the test characteristics of the Platelet Function Analyzer-100 (PFA-100) in patients treated with aspirin.

Methods and 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.

Conclusion: 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.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Analysis of Variance
  • Aspirin / administration & dosage
  • Aspirin / therapeutic use*
  • Case-Control Studies
  • Dose-Response Relationship, Drug
  • Female
  • Humans
  • Male
  • Middle Aged
  • Myocardial Ischemia / blood
  • Myocardial Ischemia / drug therapy
  • Platelet Aggregation / drug effects
  • Platelet Aggregation Inhibitors / administration & dosage
  • Platelet Aggregation Inhibitors / therapeutic use*
  • Platelet Function Tests / instrumentation*
  • Platelet Function Tests / statistics & numerical data
  • Reproducibility of Results


  • Platelet Aggregation Inhibitors
  • Aspirin