FDA Clears First Blood Test for Diagnosing Alzheimer’s Disease

In a significant medical breakthrough, the U.S. Food and Drug Administration (FDA) has cleared the first blood-based in vitro diagnostic test to aid in diagnosing Alzheimer’s disease on May 16, 2025. The Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio, developed by Fujirebio Diagnostics, Inc., is designed for adults aged 55 and older who show signs and symptoms of cognitive decline.

Addressing a Growing Public Health Concern

“Alzheimer’s disease impacts too many people, more than breast cancer and prostate cancer combined,” said FDA Commissioner Dr. Martin A. Makary. “With 10% of Americans over 65 currently affected—and that number expected to double by 2050—new diagnostic tools like this are critical.”

Alzheimer’s is a progressive neurological disorder that slowly destroys memory and thinking skills. Detecting amyloid plaques in the brain, a hallmark sign of the disease, is key to early and accurate diagnosis.

How the Blood Test Works

The new test measures the levels of two proteins in plasma—pTau217 and β-amyloid 1-42—and calculates a ratio that correlates with the presence or absence of amyloid plaques in the brain. This eliminates the need for invasive procedures like spinal taps or costly imaging options such as PET scans, which also expose patients to radiation.

Previous versions of similar tests relied on cerebrospinal fluid (CSF) obtained through lumbar puncture. The blood-based version significantly reduces patient burden and improves accessibility, especially in non-specialist or rural settings.

Clinical Trial Results and Accuracy

The FDA’s clearance was based on data from a multi-center clinical study involving 499 adults with cognitive impairment. Key findings include:

• 91.7% of participants with positive blood test results had confirmed amyloid plaques via PET scan or CSF testing.

• 97.3% of those with negative results showed no amyloid plaque.

• Fewer than 20% of tests produced indeterminate results.

These results demonstrate the test’s strong predictive value for amyloid pathology in symptomatic patients.

Limitations and Considerations

Although promising, the test for diagnosing Alzheimer’s disease does not serve as a stand-alone diagnostic tool or routine screening method.
Healthcare providers should use it alongside other clinical evaluations. The FDA noted risks of both false positives—which could lead to unnecessary treatment and distress—and false negatives, which may delay appropriate care.

Regulatory Pathway and Breakthrough Designation

The FDA reviewed the Lumipulse test through the 510(k) premarket notification process, determining it to be substantially equivalent to a previously approved CSF-based test from the same company. The blood test also received Breakthrough Device designation, an expedited pathway reserved for innovations targeting serious or life-threatening conditions.

A Milestone for Alzheimer’s Diagnosis

“Nearly 7 million Americans are currently living with Alzheimer’s,” said Dr. Michelle Tarver, Director of the FDA’s Center for Devices and Radiological Health. “Today’s clearance is an important step in making diagnosis earlier and more accessible for patients in the U.S.”

Final Words

The FDA’s decision is expected to expand diagnostic access and accelerate early intervention.
It offers new hope for patients and families affected by this devastating disease.