The purpose of this research is to evaluate instrument functionality and develop a reference range of normal data by healthy volunteers.

Inclusion Criteria:

• Age 18 years or older
• Able to consent to study

Exclusion Criteria from entire study

• Primary hemostasis diagnosis

  • Von Willebrand Disease
  • Bernard-Soulier syndrome
  • Glanzmann thrombasthenia
  • Idiopathic thrombocytopenic purpura
  • Drug-induced thrombocytopenia
  • Heparin-induced thrombocytopenia
  • Thrombotic thrombocytopenic purpura
  • Hemolytic uremic syndrome

• Participant is on anticoagulant therapy

  • Specifically thienopyrdines [Ticlopidine, Clopidogrel] and GPIIb/IIIa inhibitors [ReoPro, Aggrastat, Integrilin]

• Participant is on medication that contains ASA or aspirin (see list below in Study Procedure)

• Participant is on nonsteroidal anti-inflammatory agents that are known to induce temporary platelet dysfunction (see list below in Study Procedure)

• Participant is on non-prescription medications containing aspirin (see list below in Study Procedure)

• PFA-100 result falls outside of reference interval listed in the package insert (suggested criteria in the PFA-100 Evaluation Protocol as described in the PFA-100 System: Getting Started Guide)

• If hematocrit is less than 35%

• If platelets are less than 150 x10^3/uL

Exclusion Criteria from Cohort B but not Cohort A

• Potential for adverse reactions between current medication and aspirin as dictated by staff pharmacist
• Allergy to ASA or aspirin
• Previous allergic reaction to ASA or aspirin
• Participant is pregnant
• Asthma, or history of, with nasal polyps and rhinitis
• Stomach ulcers or bleeding
• Severe kidney disease
• Severe liver disease
• Hemophilia
• Pregnant or breast feeding

IPD will not be shared with other researchers.