No. Medicare has no single national rule that covers a tau PET scan for an Alzheimer's evaluation. Coverage is left to local Medicare contractors, so approval is case-by-case.
A tau PET scan is a brain imaging test that maps clumps of tau protein. The FDA-approved tracer Tauvid estimates the density and distribution of these tangles. It is used in adults with cognitive impairment evaluated for Alzheimer's disease, according to the Alzheimer's Association/SNMMI workgroup in the workgroup report in the Journal of Nuclear Medicine.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Official resources:
- Read the original research from NIH — Use this page to review the original research.
- Explore the official data from CMS — Use this primary source to review the underlying data.
Table of Contents
- What does a tau PET scan show?
- Why does coverage vary by place?
- How do other PET scans compare?
- When do specialists consider tau PET?
- What should you verify before scheduling?
What does a tau PET scan show?
A tau scan looks for aggregated tau tangles and where they sit in the brain. Tauvid binds to those tangles so doctors can estimate both amount and pattern. That pattern helps place memory or thinking changes in an Alzheimer's context.
It does not replace a clinical exam, cognitive testing, or other lab work. It is one piece of evidence about Alzheimer's-related brain change. A doctor decides whether that piece would alter diagnosis or care.
Why does coverage vary by place?
Medicare has not set a uniform national policy for tau PET. The same Alzheimer's Association/SNMMI workgroup notes that CMS issued no national noncoverage rule, leaving decisions to regional Medicare Administrative Contractors. Those contractors are the regional companies that process Medicare claims.
In practice, Tauvid remains covered only case-by-case despite FDA approval. Being Patient reports that patients need local-contractor and Medicare Advantage plan verification before scheduling in Being Patient's tau imaging guide. A scan approved in one region can be denied in another.
How do other PET scans compare?
Amyloid PET also moved to regional decisions. Effective October 13, 2023, CMS retired its national amyloid PET rule and ended the evidence-development requirement, according to Applied Radiology reporting on the CMS decision. Local contractors now decide amyloid PET coverage too.
FDG PET is different because it keeps national terms. Medicare retains coverage under NCD 220.6.13 for telling frontotemporal dementia apart from Alzheimer's disease after a thorough workup or through an approved study, as stated in Medicare's FDG PET coverage rule. That rule does not extend to tau PET.
When do specialists consider tau PET?
Specialists order amyloid or tau PET only when Alzheimer's is suspected and the result will change care. Examples include cognitive decline before age 65, an unusual or atypical syndrome, or a treatment-eligibility choice. Those situations come from the 2025 appropriate-use criteria described in the Alzheimer's Association appropriate-use update.
Routine memory concern alone does not meet that test. The doctor must link the scan to a clear next step, such as clarifying diagnosis or guiding therapy. Without that link, coverage and clinical value both fall.
What should you verify before scheduling?
Ask the ordering clinic to check coverage in writing for your ZIP code and plan. Hospital billing staff deal with regional rules every week. Get the expected cost if Medicare denies the claim.
- Ask which local contractor controls your claim and whether it allows tau PET for your diagnosis code.
- Ask your Medicare Advantage plan for prior-authorization rules and in-network imaging sites.
- Ask for the written order showing suspected Alzheimer's and how results will change care.
- Ask for the cash price and payment plan if you proceed without coverage.
