Comparing Plasma-Based Alzheimer’s Tests to Traditional Diagnostic Methods

When memory changes become noticeable, families often face an uncertain path to answers. Traditional Alzheimer’s testing has relied on imaging or spinal taps. Methods that, while accurate, are expensive, invasive, and often delayed until symptoms have advanced.

Today, a new option is transforming that memory health journey.

Plasma-based Alzheimer’s tests use a simple blood draw to detect brain changes linked to Alzheimer’s disease, offering clinicians and patients faster, more accessible insights. Let’s explore how plasma-based testing compares with traditional diagnostic methods and how this shift is creating earlier clarity in the care pathway.

Why Alzheimer’s Testing Is Evolving

For decades, Alzheimer’s diagnosis required multiple steps: cognitive exams, neurologist visits, and confirmatory PET scans or spinal taps.

Each step added time, cost, and stress, which often delayed diagnosis until cognitive decline became significant.

Common barriers to Alzheimer’s testing have included:

• High out-of-pocket costs for imaging and lab procedures
• Long wait times for specialist appointments
• Limited access in community or rural settings

These limitations inspired researchers to find a faster, more accessible way to evaluate brain health that complements traditional diagnostics while maintaining medical accuracy.

That innovation arrived in the form of plasma-based biomarker testing.

What Plasma-Based Alzheimer’s Tests Measure

Plasma-based Alzheimer’s tests detect measurable proteins in the blood that reflect biological changes occurring in the brain. The most well-studied of these markers, p-tau217, rises as Alzheimer’s-related tangles form in neurons. Other blood-based indicators include amyloid-β42 ratios and neurofilament light chain (NfL).

How Blood-Based Testing Differs from PET and Spinal Tap Testing

While PET imaging and cerebrospinal fluid (CSF) testing have historically been the best way to confirm Alzheimer’s, plasma-based tests measure many of the same biomarkers with far less invasiveness.

• PET scans: visualize amyloid and tau buildup directly in the brain
• Spinal taps: measure amyloid and tau levels from cerebrospinal fluid
• Plasma-based tests: assess those same biological changes through a standard or at-home blood draw

Both traditional and plasma-based tests are designed for adults experiencing memory or thinking concerns, not for asymptomatic individuals. However, plasma-based testing can detect changes at an earlier stage — before symptoms become severe or advanced. This early knowledge helps patients and clinicians act with greater confidence sooner.

Comparing Accuracy, Access, and Clinical Workflow

Plasma-based testing has shown remarkable accuracy while also expanding access to early evaluation. This combination of precision and practicality means more individuals can receive meaningful insights and timely intervention, regardless of location or access to specialty centers.

Accuracy and Reliability

Clinical studies have shown that p-tau217 blood tests can match PET and CSF findings with sensitivities and specificities of 85–90%. This precision makes plasma-based testing a credible first step in the diagnostic process.

At the 2025 Alzheimer’s Association International Conference (AAIC), we presented pilot data from 455 participants across three U.S. community sites.

• 26% showed elevated p-tau217 levels
• 80% demonstrated measurable cognitive impairment levels
• Testing with a Tasso device showed 88% accuracy and met performance requirements

These findings validate that blood-based testing can provide reliable early insights outside of a hospital or imaging center.

Access and Turnaround Time

Traditional Alzheimer’s testing can take months to schedule and years to complete.

In contrast, plasma-based testing offers quick collection and faster reporting, enabling individuals to move from concern to consultation more efficiently.

• Traditional approach: multiple clinic visits, expensive imaging, long delays
• Plasma-based approach: quick blood draw, virtual interpretation, results in days

We’ve found that plasma-based testing reduced the time from initial memory concerns to clinical intervention by 4.5 years, helping people access care sooner and with less uncertainty.

Cost and Clinical Integration

Plasma-based testing doesn’t entirely replace imaging or spinal taps — it complements them. Clinicians can now use these tests as triage tools to decide who may benefit from further confirmatory studies.

• Streamlines patient selection for PET or CSF confirmation
• Reduces unnecessary procedures and costs
• Expands diagnostic capacity in community and primary care settings

By integrating plasma-based results into standard workflows, clinicians have a chance to reach more patients earlier without compromising diagnostic precision.

The Expanding Role of Blood-Based Testing in Memory Care

Blood-based testing is rapidly moving from research into clinical practice.

Major organizations, including the Alzheimer’s Association and the National Institute on Aging, now support its inclusion in diagnostic guidelines for appropriate patients.

Physicians are increasingly integrating these tests into everyday workflows to identify who might benefit from confirmatory imaging or early treatment discussions.

As adoption grows, we aim to combine this cutting-edge science with digital accessibility and compassion by bringing expert neurologist care directly to people’s homes.

When to Consider Plasma-Based Alzheimer’s Testing

If you’re over 45 years old and noticing memory changes, or if you have a family history of Alzheimer’s, plasma-based testing can provide early clarity. It’s best suited for people who:

• Experience mild forgetfulness or confusion that sometimes disrupts daily tasks
• Have a family history of Alzheimer’s or related dementias
• Want to evaluate concerns before symptoms worsen

At Neurogen, we believe plasma-based testing is only part of a broader memory health ecosystem that connects science, technology, and human guidance.

Our goal isn’t just to deliver test results, but to build a pathway toward better understanding and earlier action.

Take the Next Step Toward Clarity

Alzheimer’s testing no longer needs to be intimidating or inaccessible. With plasma-based biomarker testing, individuals and families can gain clarity sooner, act sooner, and approach care with confidence