Inclusion Criteria- Men and women between 18 years and 75 years of age
- Recent prescription for clopidogrel or prasugrel.
- Participant is willing and able to provide informed consent.
Exclusion Criteria- Previous use of any thienopyridine within 4 months of initiating new clopidogrel or prasugrel therapy.
- Participant refusal to participate in the study.
- Anticipated discontinuation of clopidogrel or prasugrel within the 6 month study follow-up period
- Participants that have previously stated "do not contact"