The future of Alzheimer's detection: How blood-based testing is reshaping screening, diagnosis and care

One of the defining challenges in Alzheimer’s disease is the large and growing population of individuals who remain undiagnosed despite experiencing underlying cognitive impairment. An estimated 10 million to 12 million older Americans may currently fall into this category, many of whom could be evaluated for Food and Drug Administration (FDA)-cleared therapies, such as Kisunla and Leqembi, if accessible diagnostic tools were available at scale.

At the same time, demand for earlier detection and diagnosis is rising sharply as prevention strategies and preclinical treatment approaches advance, increasing the population eligible for screening. Public willingness is also high, with 4 in 5 Americans indicating they would want to know whether they are at risk of developing Alzheimer’s disease before symptoms begin.

This convergence of unmet clinical need, expanding therapeutic opportunity and strong patient demand is driving a structural shift in Alzheimer’s diagnostics. Blood-based testing is emerging as the most scalable and practical mechanism available to enable this scale of earlier detection, offering a pathway beyond amyloid positron-emission tomography (PET) imaging and cerebrospinal fluid (CSF) analysis, which remain constrained by cost, access and invasiveness.

How is the role of Alzheimer’s testing evolving for screening asymptomatic patients or at-risk populations?

Alzheimer’s testing is beginning to extend beyond symptomatic patients toward earlier and potentially presymptomatic detection. However, this remains an emerging and not yet routine application, with growing momentum driven by advances in biomarker validation and increasing therapeutic relevance.

Today, diagnostic testing is primarily concentrated in patients with cognitive impairment. Expanding screening to asymptomatic populations represents a fundamentally different pathway, requiring distinct regulatory, clinical and reimbursement frameworks.

Policy efforts such as the ASAP Act reflect growing recognition of the need to accelerate earlier testing and broaden access, but widespread adoption in asymptomatic populations is still in its early stages.

Together, this shift challenges the traditional model of specialist-driven diagnosis after symptom onset, moving instead toward earlier identification within broader at-risk populations.

What is pTau217?

As one of the most widely studied biomarkers for Alzheimer’s disease, pTau217, is a specific form of the tau protein that has undergone phosphorylation, a process in which phosphate groups are added to the protein. Research has shown that elevated levels of pTau217 in the blood are strongly associated with the presence of amyloid plaques and tau pathology in the brain, two key hallmarks of Alzheimer’s disease, making it one of the most accurate and extensively validated biomarkers for identifying underlying disease.

How is pTau217 changing the way clinicians and researchers think about Alzheimer’s detection compared with PET and CSF?

Compared with PET imaging and CSF analysis, emerging blood-based biomarkers demonstrate increasingly strong concordance with these established modalities in detecting Alzheimer’s pathology. Amyloid PET scans remain the historical “gold standard,” with CSF as a secondary reference, but emerging blood-based biomarkers have now reached comparable accuracy levels in robust real-world clinical validation.

The key shift is less about replacing existing modalities outright and more about improving accessibility and scalability. Blood-based biomarkers have already transformed research workflows by enabling faster, less invasive screening and longitudinal monitoring in clinical trials. With FDA-cleared blood tests now available to help assess whether patients with cognitive impairment may have underlying amyloid pathology, these tools are also beginning to play a larger role in clinical care. For clinicians to trust blood tests at the same level as PET scans, the evidence threshold remains clear: robust real-world clinical validation, regulatory approval, and seamless integration into clinical workflows.

Among these biomarkers, pTau217 has emerged as one of the most extensively studied and validated, with growing broad adoption across research and emerging clinical diagnostic settings.

In what ways could blood-based testing reshape the current Alzheimer’s diagnostic bottleneck?

The current diagnostic pathway is constrained by significant delays and specialist bottlenecks.

Patients with cognitive concerns are typically referred from primary care to neurology, often facing wait times up to a year. During this period, disease progression may continue without intervention.

Blood-based testing offers a pathway to shift initial screening into primary care settings, enabling earlier triage of patients who may have underlying amyloid pathology. This would allow more efficient prioritization for specialist evaluation and confirmatory imaging where appropriate.

The result is a more efficient diagnostic flow, reducing delays and enabling earlier intervention in the course of the disease.

If Alzheimer’s pathology can be detected earlier in the disease continuum, how does that reshape conversations around prognosis, monitoring and clinical management?

Earlier detection fundamentally shifts Alzheimer’s disease from a late-stage diagnosis model toward earlier disease management with more proactive clinical intervention. Identifying pathology before or during mild cognitive impairment allows patients to enter diagnostic confirmation and treatment pathways sooner, when interventions are likely to be more effective.

This is particularly significant as disease-modifying therapies continue to emerge, increasingly targeting amyloid pathology earlier in the disease continuum. It has also created the potential for longitudinal monitoring and earlier conversations around prognosis, rather than reactive management after significant cognitive decline.

How could a blood-first diagnostic pathway change the economic and resource burden of Alzheimer’s testing at a system level?

A blood-first diagnostic model has the potential to materially reduce both cost and overall health care system burden.

Primary care physicians operate under significant time constraints, which currently drive specialist referrals and downstream imaging demand. A simple blood test could be integrated into routine primary care screening, similar to lipid or metabolic panels, shifting initial assessment into a lower-cost, high- throughput setting.

From a cost perspective, the difference is substantial. PET imaging can cost several thousand dollars per scan, while blood-based tests are priced in the low hundreds under current reimbursement benchmarks. At scale, this shift enables broader population screening at lower cost while reducing pressure on specialist services and imaging infrastructure.

What is the cost-benefit ratio of blood tests versus PET or CSF analysis?

Blood-based tests offer a fundamentally more cost-efficient approach to Alzheimer’s diagnostics while maintaining strong diagnostic accuracy.

From a payer perspective, they represent a more sustainable model for large-scale screening, particularly as aging populations drive increasing diagnostic demand. However, the overall economic impact depends on how they are integrated into clinical workflows, not solely on unit cost.

Regulatory and reimbursement frameworks are still evolving. FDA clearance is a critical prerequisite in the U.S., alongside payer coverage decisions, particularly from Medicare. In Europe, CE marking plays a similar enabling role.

These systems are beginning to adapt, but reimbursement and coverage remain key gating factors for widespread clinical adoption.

What is the biggest misconception about blood-based Alzheimer’s testing?

The most common misconception is that blood-based tests will replace PET imaging for Alzheimer’s disease diagnosis. In reality, these tests are not intended to replace PET or CSF as standalone definitive diagnostics. They function primarily as high-performing triage tools that inform downstream clinical decision-making.

Another misconception is that research validation alone is sufficient for clinical adoption. Clinicians require real-world evidence, workflow integration, and clear guidance on next steps following a test result. Adoption depends as much on usability and system integration as it does on analytical accuracy.

As these elements come together, blood-based testing is increasingly positioned as a practical entry point into Alzheimer’s evaluation, helping unlock earlier identification at scale and supporting a more proactive, prevention-oriented model of care.

Looking ahead, how do you see blood-based biomarkers reshaping the Alzheimer’s diagnostic and treatment landscape over the next five to 10 years?

Over the next decade, blood-based biomarkers are expected to become embedded into routine preventive screening for older adults, alongside standard blood panels. The emerging model is age-based screening in primary care, with follow-up diagnostic pathways activated as clinically indicated. This would enable earlier identification of Alzheimer’s pathology, potentially even before symptom onset.

However, this shift depends on alignment across regulatory approval, therapeutic availability, reimbursement frameworks, clinical guidelines, and integration into health care systems. When these elements converge, Alzheimer’s care will shift from a reactive diagnosis model to a proactive, longitudinal screening paradigm, fundamentally changing how the disease is detected and managed.

Mike Banville is CEO and president of ALZpath, whose mission is to empower early, accurate and accessible Alzheimer’s disease diagnosis, transforming how the disease is detected, treated and prevented.