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FDA approves test that can rule out Alzheimer’s disease

The test will aid diagnosis of patients with some dementia symptoms

Updated:

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By:
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Mark Huffman
Reporter

Mark Huffman has covered consumer issues since 2004, with a special focus on protecting and empowering older adults. A former news correspondent for the Associated Press Radio Network, Westwood One, and ConsumerAffairs, Mark brings decades of journalistic experience to RetirementLiving.com. He is passionate about giving consumers a voice and helping them make informed decisions. Mark has also created educational content, including Senior Scam Alert, a video resource designed to help seniors recognize and avoid fraud. He holds a B.A. from the University of Kentucky and lives with his family in Richmond, Virginia.
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Key Insights

  • The U.S. Food and Drug Administration has approved a novel blood test capable of ruling out Alzheimer’s disease in patients showing signs of cognitive decline — a first-of-its-kind clearance.
  • The new diagnostic tool promises a less invasive, faster, and more accessible alternative to PET brain scans or spinal taps, potentially streamlining the Alzheimer’s evaluation pathway.
  • Early data suggest the test offers very high negative‐predictive accuracy, meaning a negative result strongly reduces the likelihood of underlying Alzheimer’s pathology.

The U.S. Food and Drug Administration has cleared a blood‐based diagnostic test that can reliably exclude Alzheimer’s disease in symptomatic patients. The approval could mark a turning point in how clinicians will approach cognitive decline and memory loss in older adults, offering a simpler path to rule out one of the most feared causes of dementia.

The test, developed by Fujirebio Diagnostics under the brand name Lumipulse, measures levels of two proteins in the blood — pTau217 and β-amyloid 1-42 — and calculates a ratio that correlates with the presence or absence of amyloid plaques, a pathologic hallmark of Alzheimer’s.

In clinical trials involving nearly 500 participants, the test yielded a negative predictive value in the high 90-percent range.  Crucially, the FDA’s approval emphasizes use in ruling out Alzheimer’s: patients with negative results may avoid further invasive or costly testing, while those with positive findings would proceed to confirmatory imaging or cerebrospinal fluid (CSF) assays. 

How it works

Under the approved label, the test is intended for adults aged 55 or older who exhibit signs or symptoms of cognitive impairment, such as memory lapses, difficulty with planning or problem solving, or other early indicators.  It is not recommended as a general screening tool in asymptomatic individuals, due to the possibility of false positives or negatives in lower‐risk populations. 

The test operates using a standard blood draw. Laboratories analyze plasma for the two biomarkers and compute their ratio. The resulting score is then interpreted in the context of clinical and cognitive assessments. 

If the result is negative – below a certain threshold – physicians can be reasonably confident that Alzheimer’s is unlikely and consider alternative diagnoses or follow monitoring. Conversely, if the result is positive or borderline, the usual next steps include PET imaging, CSF testing, or neurologic evaluation. 

Compared to PET scans and lumbar puncture, the new test is significantly more convenient, less expensive, and less invasive. PET imaging requires expensive tracer compounds and specialized scanners, while lumbar puncture involves collecting cerebrospinal fluid and carries procedural discomfort and risk. 

What it means for patients and physicians

Prospective Benefits

  1. Faster detection and reassurance
    For many patients and their families, getting a dependable negative result earlier can reduce uncertainty and speed clinical decision making.
  2. Reduced reliance on invasive tests
    This test offers a front‐line, lower burden filter before escalating to more specialized or invasive diagnostics.
  3. Improved access and equity
    Because it requires only a blood draw, the test can be more widely deployed into community and outpatient settings beyond major academic centers.
  4. Better targeting of Alzheimer’s therapies
    Some Alzheimer’s treatments currently in use or development require confirmation of amyloid pathology. This test could help triage candidates more efficiently.

Limitations and risks

  1. False positives/negatives
    Though highly accurate, the test is not perfect. A small fraction of negative results may miss underlying disease (false negatives), and some positive results may mislead clinicians if the patient’s condition is due to another cause.
  2. Need for confirmatory testing in positives
    A positive result is not a definitive diagnosis of Alzheimer’s; it indicates increased probability and typically triggers further evaluation.
  3. Not designed for general screening
    Its use is limited to symptomatic individuals. Applying it broadly to asymptomatic populations could yield misleading results.
  4. Interpretation context matters
    Physicians must integrate test results with cognitive testing, imaging, medical history, and differential diagnoses.
  5. Insurance coverage & cost
    Though FDA clearance opens the door, wide insurance reimbursement (e.g. Medicare/Medicaid) is not guaranteed immediately. The out-of-pocket cost to patients remains uncertain at present.