Short answer: Medicare covers home PT/INR monitoring for certain people who take warfarin for a mechanical heart valve, chronic atrial fibrillation, or venous thromboembolism. The monitor and testing must be prescribed, and all national coverage conditions must be met.
Original Medicare coverage
Home INR testing measures blood clotting time so a treating clinician can manage chronic warfarin therapy. The CMS national coverage determination applies to people using warfarin for a mechanical heart valve, chronic atrial fibrillation, or venous thromboembolism, including deep vein thrombosis and pulmonary embolism.
Coverage can include the home testing monitor, supplies, and related management services when the claim and documentation meet Medicare rules. Home monitoring for other indications may depend on the local Medicare contractor.
Eligibility and limits
The person must have been anticoagulated for at least three months before using the home device. A treating physician must prescribe the monitor and testing. The person must complete a face-to-face education program on anticoagulation management, demonstrate correct use of the device, and continue to use it correctly. Medicare’s national rule allows self-testing no more often than once per week.
This national policy concerns warfarin management. It should not be applied to other blood thinners that do not use INR monitoring.
Costs
Home INR services are generally covered under Part B. The Part B deductible and coinsurance may apply to the equipment, supplies, and monitoring services. The amount owed depends on the Medicare-approved amount, assignment, and how the service is billed.
Medicare Advantage
Medicare Advantage plans must cover services that meet Original Medicare’s national coverage rule. A plan may require network laboratories or suppliers, prior authorization, and different cost sharing.
What to do next
- Confirm that warfarin is being used for a condition listed in the national policy.
- Ask the treating physician about the required training and written order.
- Verify that the testing service and supplier are enrolled in Medicare.
- Ask how the monitor, supplies, and professional review will be billed.
Sources
Last reviewed: August 2026. Medicare rules and plan benefits can change.