A new Viewpoint published today in JAMA highlights major advancements—and critical challenges—surrounding the rapid expansion of blood‑based biomarkers for Alzheimer’s disease (AD). The article, authored by Dr. Heather Whitson and colleagues, examines how recently FDA‑cleared plasma tests could dramatically increase access to biological diagnoses of Alzheimer’s while also posing unintended risks for patients.

In 2025, two landmark approvals reshaped the diagnostic landscape:

• Fujirebio’s Lumipulse G pTau 217/β‑Amyloid 1‑42 plasma ratio test, the first FDA‑cleared blood test to detect AD pathology.
• Roche’s Elecsys pTau‑181 plasma test, cleared to help rule out Alzheimer’s disease in primary care settings

These innovations offer a minimally invasive and cost‑effective alternative to spinal taps and PET scans, significantly widening access to diagnosis—an especially important step as new anti‑amyloid therapies continue to emerge.

However, the authors caution that widespread clinical use may magnify disparities and introduce new harms if implementation is not carefully managed. Key concerns include:

Risk of Misdiagnosis

Blood test accuracy varies across platforms, and results depend heavily on a patient’s pretest probability of AD. False‑positives may lead to anxiety and unnecessary interventions, while false‑negatives could delay needed care. Chronic conditions—such as kidney disease, obesity, or use of common heart‑failure medications—can also distort biomarker levels.

Unequal Access to Follow‑Up Care

Many test results require confirmation via PET scan or lumbar puncture. Without accessible follow‑up, patients may receive information that cannot be adequately acted upon, perpetuating inequities in diagnosis and treatment.

Legal and Psychological Risks

Learning one’s biomarker status—even before symptoms appear—can trigger anxiety, affect employment or insurance eligibility, and introduce legal vulnerabilities for patients and their families.

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Recommendations for Moving Forward

The JAMA authors call for coordinated action to ensure safe, equitable adoption of blood‑based AD testing:

• Expand clinician and public education on test limitations and interpretation.
• Strengthen legal protections for individuals receiving biomarker diagnoses.
• Increase research on test performance in diverse and medically complex populations.
• Improve reimbursement and access to confirmatory diagnostics and follow‑up care.

“As the field advances, the urgency to diagnose AD biologically will only grow,” the authors write, emphasizing that these new tools must be implemented responsibly to avoid widening existing health disparities.”

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Whitson HE, Fowler NR, Mielke MM. Blood-Based Biomarkers for Alzheimer Disease: Preventing Unintended Consequences. JAMA. Published online January 22, 2026. doi:10.1001/jama.2025.26049