The ability to explain bleeding or clotting complications in patients treated with rivaroxaban remains challenging. In addition, there is limited data on how coagulation tests perform in patients treated with therapeutic doses of rivaroxaban. Predicted responses of coagulation tests to therapeutic doses of rivaroxaban may be helpful in better understanding abnormal responses to rivaroxaban. The purpose of the study is to define a therapeutic reference range for peak and trough coagulation tests in patients taking FDA approved doses of rivaroxaban and to determine which tests may be most clinically useful for monitoring rivaroxaban.

Inclusion Criteria:

Person taking therapeutic dose of Rivaroxaban

Exclusion Criteria:

• CrCl < 15 mL/min
• Non-FDA approved dose based on calculated CrCl with most recent SCr
• Age < 18 years
• Inability to communicate in the English language
• Decisionally-impaired individuals
• Incarcerated
• Pregnant/Lactating (Pregnancy category: C, unevaluated effects in lactation)

Patients taking FDA-approved doses of rivaroxaban and control subjects not taking an anticoagulant or antiplatelet were eligible for inclusion