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JAMA Diagnostic Test Interpretation
October 9, 2018

Coagulation Test Interpretation in a Patient Taking Direct Oral Anticoagulant Therapy

Author Affiliations
  • 1Department of Medicine, University of Toronto, Toronto, Ontario, Canada
  • 2Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
  • 3Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
JAMA. 2018;320(14):1485-1486. doi:10.1001/jama.2018.13998

A 74-year-old man presented with spontaneous, acute onset of confusion and headache. He had no preceding head trauma or falls. He had a history of atrial fibrillation with an annual stroke risk of 2.9% (based on points accrued for hypertension and age ≥65 years using the CHA2DS2-VASc score1). He was being treated with rivaroxaban, 20 mg daily. He took his last dose 14 hours prior to presentation. Other medications included ramipril and rosuvastatin.