Medicare gridlock stalls alzheimer’s blood test rollout

By late October 2026, the case for pushing the ASAP Act had sharpened because Medicare still treated coverage as a separate hurdle after FDA action. As Medicare’s Breakthrough Device Coverage Pathways Explained put it, “FDA authorization does not mean Medicare pays,” and the gap to durable coverage “routinely runs years,” leaving advocates to target the statutory bottleneck directly rather than wait on either a National Coverage Determination or a patchwork of Medicare Administrative Contractor decisions that could delay payment for FDA-approved Alzheimer’s blood tests.

That lobbying intensified when existing federal shortcuts looked either failed or too narrow to solve the problem at scale. Medicare’s Breakthrough Device Coverage Pathways Explained notes that MCIT—“finalized January 2021, repealed November 2021”—had promised four years of automatic national coverage on FDA authorization but “never took effect,” while TCET is “capped at roughly five devices a year,” requires nomination “18–24 months” before an FDA decision, and has seen “Exactly one device” publicly enter; with RAPID’s comment period closing October 13, 2026, and CMS finalizing repeal of IPPS and OPPS alternative breakthrough payment pathways starting with FY 2028 applications, late-October lobbying around ASAP became the clearest route to secure Medicare coverage.

What the lobbying is really acknowledging is that clinical credibility alone does not make Alzheimer’s blood tests routine; reimbursement architecture does. The Clinical Trial Vanguard noted that the FDA cleared Fujirebio’s Lumipulse G pTau217/Beta-Amyloid 1-42 Plasma Ratio as the first in vitro diagnostic blood test for Alzheimer’s disease, and on August 25, 2026 cleared Roche’s Elecsys Phospho-Tau Plasma test, while also reporting that plasma pTau217 prescreening cut trial screen-failure rates from 75% to below 25% and improved diagnostic accuracy in primary and specialty care, leaving payment and coverage as the practical bottleneck.

That is why policy support has shifted upstream into trial design and Medicare process: Clinical Trial Design and Strategic Challenges in CMS’s RAPID Pathway found Medicare-facing endpoints can “plausibly add twenty to forty percent to cost and six to eighteen months to timeline,” and that “the calculus is straightforward for a company whose Medicare mix is 70 percent” but far less so at 25 percent. RAPID Introduces Pre-Trial Medicare Device Coverage Pathway shows CMS trying to solve that by posting a proposed NCD the day FDA authorizes a product and finalizing coverage within 60 or 90 days, yet warning that RAPID “says nothing about coding or payment,” so a RAPID device could hold a shiny final NCD 60 days after authorization and still be waiting on a HCPCS code and a payment rate, even as CMS is eliminating alternative NTAP and device pass-through pathways beginning with FY 2028 applications.

Real-world use is no longer hypothetical: Bioengineer.org reported that between January and December 2025, researchers analyzed 1,368 consecutive patients across 24 secondary and tertiary care centers and found plasma p-tau217 already changing dementia workups because it “behaves distinctly across different clinical presentations.” But that same scale exposed why rollout is not a simple yes-or-no proposition: “equivocal results were common: 19.9% of all tests fell into this gray zone, and they were more frequent in older individuals,” creating exactly the kind of practical friction that makes implementation rules matter.

How the test performs also depends heavily on who is being tested and why. Patients were grouped by referring clinicians’ diagnostic hypotheses—997 suspected Alzheimer’s disease, 180 suspected non-Alzheimer cognitive disorders, and 191 with no specific etiological hypothesis; positivity was “66.1% versus 17.8%,” with the no-hypothesis group in between, while plasma p-tau217 “increased with age,” “were higher in women,” “were inversely correlated with MMSE scores,” and “were inversely correlated with renal function,” leading the authors to “explicitly recommend integrating” patient-specific factors and pre-test probability into interpretation.

Those nuances matter because the test is already altering workflow. In a survey of 53 prescribers, “71% reported increased confidence,” “80% reported a shorter diagnostic delay,” and “63% reported reduced use of brain fluorodeoxyglucose positron emission tomography,” while the authors cautioned the evidence was observational and cross-sectional; in 117 patients with paired measurements, plasma p-tau217 correlated with the CSF p-tau181/Aβ42 ratio (Spearman correlation coefficient “0.640”) and showed discrimination for a positive ratio above “0.10” (AUC “0.870”), strong enough to support use but not eliminate case-level uncertainty.