It is estimated that about 2 million Americans each year are victims of deep vein thrombosis (DVT). Pulmonary embolism (PE), a potentially life-threatening condition, is a possible consequence of DVT. PE occurs if a blood clot breaks free from a larger vein then travels and enters the pulmonary circulation; where it can compromise breathing.¹ Many DVT and PE patients require oral anticoagulation therapy to reduce the risk of recurrence or related medical complications.

Now some DVT and PE patients can improve the safety of anticoagulation therapy. On March 19, 2008, a national coverage policy entitled, Decision Memo for Prothrombin Time (INR) Monitor for Home Anticoagulation Management, was released. The memorandum supports coverage for Medicare patients with DVT or PE to perform weekly, at home INR testing with a portable INR monitor that has been approved by the US Food and Drug Administration.² This approach to INR monitoring, termed “patient self-testing”, allows DVT and PE patients to monitor warfarin blood levels from the comfort of home.

Medicare decided to support more frequent testing only after a thorough review of existing clinical data and research studies.² Importantly, when compared to monthly INR monitoring, weekly testing results in better control of warfarin dosing, which leads to fewer bleeding episodes and a reduced risk of stroke.³

A 2001 decision to extend coverage for weekly home INR testing to warfarin patients with mechanical heart valves set the precedent for the 2008 Medicare proposal. As with the 2001 coverage criteria, patients with DVT or PE must i) have a physician’s prescription, and ii) have been taking warfarin (Coumadin ®) for 90 days or more.² Reimbursement for the monitor and testing supplies requires that the patient completes face-to-face training from a healthcare professional and continues to competently use the device, according to a physician’s instructions.²

Patients interested in home INR testing should speak with their physician about the improved time-in-range more frequent testing may provide. The home page of www.pt-inr.com provides patients with basic information about getting started and how home INR testing can improve the safety of warfarin therapy. Patient self-testing is not a substitute for routine physician care.