Diagnostic Tests (other)
This may not be an exhaustive list of all applicable Medicare benefit categories for this item or service.
Use of the International Normalized Ratio (INR) or prothrombin time (PT) - standard measurement for reporting the blood's clotting time - allows physicians to determine the level of anticoagulation in a patient independent of the laboratory reagents used. The INR is the ratio of the patient's PT (extrinsic or tissue-factor coagulation pathway) compared to the mean PT for a group of normal individuals. Maintaining patients within his/her prescribed therapeutic range minimizes adverse events associated with inadequate or excessive anticoagulation such as serious bleeding or thromboembolic events. Patient self-testing and self-management through the use of a home INR monitor may be used to improve the time in therapeutic rate (TTR) for select groups of patients. Increased TTR leads to improved clinical outcomes and reductions in thromboembolic and hemorrhagic events.
Warfarin (also prescribed under other trade names, e.g., Coumadin®) is a self-administered, oral anticoagulant (blood thinner) medication that affects the vitamin K-dependent clotting factors II, VII, IX and X. It is widely used for various medical conditions, and has a narrow therapeutic index, meaning it is a drug with less than a 2-fold difference between median lethal dose and median effective dose. For this reason, since October 4, 2006, it falls under the category of a Food and Drug Administration (FDA) “black-box” drug whose dosage must be closely monitored to avoid serious complications. A PT/INR monitoring system is a portable testing device that includes a finger-stick and an FDA-cleared meter that measures the time it takes for a person’s blood plasma to clot.
Indications and Limitations of Coverage
B. Nationally Covered Indications
For services furnished on or after March 19, 2008, Medicare will cover for the use of home PT/INR monitoring for chronic, oral anticoagulation management for patients with mechanical heart valves , chronic atrial fibrillation, or venous thromboembolism (inclusive of deep venous thrombosis and pulmonary embolism) on warfarin. The monitor and the home testing must be prescribed by a treating physician as provided at 42 CFR 410.32(a), and all of the following requirements must be met:
- The patient must have been anticoagulated for at least 3 months prior to use of the home INR device; and,
- The patient must undergo a face-to-face educational program on anticoagulation management and must have demonstrated the correct use of the device prior to its use in the home; and,
- The patient continues to correctly use the device in the context of the management of the anticoagulation therapy following the initiation of home monitoring; and,
- Self-testing with the device should not occur more frequently than once a week.
C. Nationally Non-Covered Indications
1. All other indications for home PT/INR monitoring not indicated as nationally covered above remain at local Medicare contractor discretion.
2. This national coverage determination (NCD) is distinct from, and makes no changes to, the PT clinical laboratory NCD at section 190.17 of Publication 100-03 of the NCD Manual.
(This NCD last reviewed March 2008)
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