The Prevalence of Nontherapeutic and Dangerous International Normalized Ratios Among Patients Receiving Warfarin in the Emergency Department

The prevalence of undesirable INR in the ED is higher than in warfarin populations previously studied, and a significant number of nontherapeutic levels were associated with thromboembolism, stroke, or hemorrhage. Given the prevalence and established danger of subtherapeutic and supratherapeutic levels, a low threshold should be maintained for testing and addressing INR levels in patients receiving warfarin in the ED.