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
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
