The purpose of this study is determine whether point of care coagulation testing is able to map the anticoagulatory effects of new oral anticoagulants dabigatran and rivaroxaban. Used as devices are thrombelastometry/-graphy (ROTEM, TEG)and multiple platelet function analyzer (Multiplate).

Patients receiving dabigatran or rivaroxaban in therapeutic doses are recruited. Blood will be taken twice in correlation to the time of drug intake (before and 3 hours after drug intake). The results of thrombelastometry/-graphy and multiple platelet function analyzer will be compared directly with the concentrations determined by plasma concentration assays.

Inclusion Criteria:

• Patients receiving Dabigatran or Rivaroxaban
• Adults > 18 years

Exclusion Criteria:

• Patients receiving concomittantly inhibitors of platelet function
• Renal insufficiency (Creatinine > 1,5 mg/dl), Urea > 80 mg/dl)
• Hemodialysis
• Hepatic Dysfunction (AST > 30 U/l, ALT > 30 U/l)

Primary Care Clinic. Patients with non-valvular atrial fibrillation who receive Dabigatran or Rivaroxaban for prevention of stroke and systemic embolism.