Reviewed by the Help Dementia Editorial Team — our editors review every article for accuracy against guidance from the National Institute on Aging, the Alzheimer’s Association, and peer-reviewed sources.
Yes, new Alzheimer’s blood tests could widen health inequality unless access barriers are addressed. While two FDA-approved blood biomarker tests arrived in 2025 with impressive accuracy—demonstrating 90% negative predictive value for ruling out Alzheimer’s disease—their potential to reduce diagnostic delays sits in tension with harsh realities: Medicare doesn’t cover them, rural diagnostic infrastructure remains sparse, and the research validating these tests was conducted almost exclusively in white populations. A 55-year-old with private insurance and access to a neurologist in an urban center can get a simple, affordable blood test; a rural patient on Medicare or someone from an underrepresented racial group faces a very different diagnostic pathway.
The promise of blood-based biomarkers is genuine. These tests are less invasive and far cheaper than the previous gold-standard approaches—PET imaging and lumbar punctures, both costing upward of $10,000. Yet without insurance coverage, geographic distribution of specialists, and rigorous validation in diverse populations, these advances risk becoming tools that primarily serve those who already have medical privilege. The question is not whether the tests work, but whether the healthcare system will make them equitably available.
Table of Contents
- Who Can Actually Access These New Blood Tests?
- The Coverage Crisis and Its Real Consequences
- Racial and Ethnic Disparities in Biomarker Development and Validation
- Cost as a Barrier: Blood Tests Versus Older Methods
- Geographic Disparities and Rural Diagnostic Deserts
- Chronic Kidney Disease, Obesity, and Biomarker Interpretation
- The Path Forward: Policy and Equity
- Conclusion
Who Can Actually Access These New Blood Tests?
The two blood tests approved in 2025 measure plasma phosphorylated tau (pTau217) and amyloid-beta ratios—biomarkers that correlate with Alzheimer’s pathology in the brain. They’re faster and less burdensome than invasive alternatives. But approval by the FDA is not the same as real-world access. Medicare, which covers approximately 19 million Americans aged 65 and older, has not included these blood biomarker tests in its coverage decisions. This means an older adult on Medicare must either pay out-of-pocket, often $500 to $1,500 per test, or rely on their provider’s willingness to order it as an uninsured service.
Private insurers vary widely in coverage, leaving insurance status as a major determinant of who gets tested. The contrast with older imaging methods illustrates the access gap. While the Centers for Medicare & Medicaid Services (CMS) did lift a one-scan-per-patient restriction in 2023 and unbundled payment for radiopharmaceuticals in 2024—making amyloid PET imaging more accessible to some—coverage remains fragmented. A patient with excellent insurance in a major medical center can access multiple diagnostic pathways; a patient in a rural area without specialists, or someone without insurance, faces a linear progression of barriers. One important note: the Lumipulse pTau217/Aβ42 plasma test was recalled in early 2026 due to false-positive concerns in specific manufacturing lots. This kind of manufacturing issue underscores that FDA approval alone does not guarantee consistent performance across all test runs, especially in populations not well-represented in validation studies.
The Coverage Crisis and Its Real Consequences
Medicare’s exclusion of blood biomarker tests from coverage contradicts their cost-effectiveness. Research shows that blood-based biomarker testing identifies 98.2% of PET-positive patients with a lower average cost per diagnosis compared to traditional PET imaging. From a public health standpoint, this should be a no-brainer: a cheaper test that works well, covered by the program that serves the most vulnerable older Americans. Yet policy has not moved in this direction, leaving older adults and their physicians making private decisions about whether to pay for a test Medicare won’t reimburse. The practical consequence is a two-tier diagnostic system.
A 68-year-old insured patient can walk into a specialist’s office, request the blood test, and have results in weeks. The same test can take months or never happen for a Medicare patient of limited means, deferring diagnosis and treatment initiation. This delay matters because early intervention with emerging treatments like amyloid-targeting monoclonal antibodies is most effective in the early stages of cognitive decline. By the time an uninsured or Medicare-only patient gets a diagnosis through older, slower methods, they may have progressed beyond the window where these treatments help. The Alzheimer’s Screening and Prevention Act has been proposed to create a Medicare coverage pathway for these FDA-approved blood biomarker screening tests, but legislative action remains pending. Until that changes, the new tests will remain a privilege of the insured and the wealthy.
Racial and Ethnic Disparities in Biomarker Development and Validation
The research underlying these blood tests was conducted in predominantly white populations. Major validation studies included over 96% white participants, with less than 2% Black, Asian, or Hispanic participants—a stark underrepresentation that raises serious questions about whether the tests perform equally across all populations. This is not an abstract concern. Chronic kidney disease and obesity, which are more prevalent in non-white populations and can affect how biomarkers appear in blood, have different relationships to amyloid and tau pathology across populations. A test validated in a 96% white sample may interpret results differently when applied to a Black or Latino patient. The disparity gap is especially troubling because Black Americans bear a disproportionate burden of dementia and Alzheimer’s disease. They are diagnosed later, treated less often with disease-modifying therapies, and experience worse outcomes.
One might expect that groups most affected by a disease would be best represented in the research validating new diagnostic tools. Instead, the pattern is reversed. The blood tests that could help equalize diagnosis across racial groups were developed and validated in ways that may perpetuate diagnostic disparities. A concrete example: a 60-year-old Black woman with subjective cognitive complaints and risk factors like high blood pressure and diabetes goes to her doctor. She gets a blood biomarker test developed and validated in a population that looked very different from her. Even if the test is accurate, her provider may interpret it differently, or the biomarker cutoffs developed in white cohorts may not apply to her clinical presentation. This is not speculation—it’s a documented pattern in diagnostic medicine where validation studies lack diversity.
Cost as a Barrier: Blood Tests Versus Older Methods
Blood-based biomarker tests, costing typically $500 to $1,500, are substantially less expensive than the diagnostic alternatives. A PET scan for amyloid or tau can exceed $5,000, and a lumbar puncture for cerebrospinal fluid biomarkers, though sometimes cheaper than imaging, carries medical risks and is available in few centers. The financial comparison seems clear: the new tests are more accessible. Yet this cost advantage is meaningless without coverage. For a wealthy patient without insurance, $1,500 is an inconvenience.
For a working-age person or a retiree on fixed income without insurance, it’s prohibitive. And for a Medicare patient, the issue is not just the out-of-pocket cost but the principle: why should they pay for a test that doctors agree is reliable and cost-effective, when the same program covers more expensive alternatives? A patient might choose not to pursue diagnosis at all if it requires paying for a test that seems like it should be covered. The real inequality here is not about the test itself but about the coverage decisions that determine who can access it. A 62-year-old with an employer health plan and a $2,000 deductible faces a different calculus than a 72-year-old on Medicare with no supplemental coverage. The tests level the diagnostic playing field only for those who can reach the field in the first place.
Geographic Disparities and Rural Diagnostic Deserts
Rural America faces a compounding problem: even if blood biomarker tests become widely available and covered, the infrastructure to interpret them, order appropriate follow-up imaging, and deliver disease-modifying treatments is concentrated in cities and large medical centers. A rural patient who gets a positive blood test may then need to travel 50 or 100 miles to a neurologist or memory center for confirmation with PET imaging or to discuss amyloid-targeting monoclonal antibodies. Rural areas lack the diagnostic infrastructure—PET imaging centers, specialists trained in dementia care, and infusion centers for monoclonal antibody treatment—that urban patients take for granted. This creates a diagnostic limbo.
The blood test can be done anywhere—that’s one of its major advantages. But the result often requires further workup and specialist interpretation. A rural physician may feel uncertain about how to counsel a patient with a positive blood biomarker result without neurologic consultation, yet getting that consultation means a significant trip. The convenience of the blood test evaporates when the entire diagnostic journey requires geographic privilege. Studies have documented that rural patients experience diagnostic delays and are less likely to access emerging treatments for Alzheimer’s disease, and this pattern is likely to persist even as blood biomarkers improve initial screening.
Chronic Kidney Disease, Obesity, and Biomarker Interpretation
The blood biomarkers measured in these tests—phosphorylated tau variants and amyloid-beta ratios—exist in a complex biological context. Chronic kidney disease and obesity alter how these biomarkers appear in blood and may affect their interpretation independently of Alzheimer’s pathology. These comorbidities are more prevalent in Black and Latino populations, meaning that even if the tests were validated in diverse cohorts, the clinical interpretation in patients with these conditions would still introduce systematic bias. This is not a minor technical detail.
It means that a biomarker cutoff developed in a cohort with low obesity and preserved kidney function may need adjustment for patients with different metabolic profiles. Yet the tests are being introduced without that kind of population-specific validation. A patient with both obesity and early kidney disease might have a positive blood test not because they have more Alzheimer’s pathology, but because their metabolic status affects biomarker levels. Without population-specific research, clinicians and patients won’t know how to interpret the result.
The Path Forward: Policy and Equity
The promise of blood-based biomarkers can only be realized if three things happen: Medicare coverage, diverse validation studies, and geographic distribution of diagnostic expertise. The Alzheimer’s Screening and Prevention Act represents movement on the coverage front, but it remains in the policy pipeline. Validation studies in Black, Latino, Asian American, and rural populations are beginning, but they are underfunded relative to the need. And the distribution of specialists and treatment infrastructure remains tied to economic geography that no blood test can fix alone.
What matters most is intent. Policymakers and researchers can choose equity or accept inequality as the default. Blood biomarkers offer a chance to democratize Alzheimer’s diagnosis by making it cheaper, simpler, and less burdensome. That chance will be wasted if the benefits accrue only to the already-privileged. The tests themselves are equitable tools; the system for deploying them is not.
Conclusion
New blood-based Alzheimer’s biomarker tests represent a genuine diagnostic advance, offering higher accuracy and lower burden than invasive alternatives. Yet without Medicare coverage, validation in diverse populations, and geographic distribution of diagnostic expertise, these tests will likely widen the gap between those who can access early diagnosis and those who cannot. Inequality is not built into the science; it’s built into healthcare policy and research design decisions that can be changed.
If you or a family member are concerned about cognitive changes, speak with your primary care doctor about what diagnostic options are available and covered by your insurance. Advocate for Medicare coverage of blood biomarker tests. Support diverse representation in research. The science is ready; the healthcare system needs to catch up.
