Historic FDA Approval: The First Blood Test for Alzheimer's Diagnosis Enters Use

A New Era in Alzheimer's Diagnosis

The US Food and Drug Administration (FDA), on May 16, 2025, approved the first blood test to aid the early diagnosis of Alzheimer's disease . The test provides an alternative to the brain imaging (PET) or cerebrospinal fluid (CSF) testing previously required to detect beta-amyloid plaques and tau protein deposits by identifying them from a blood sample.

Alzheimer's diseaseis among the most common neurodegenerative diseases in older adults worldwide. Now, testing can beeasier, faster and less invasive: Alzheimer's biomarkers can be measured in blood without a PET scan.

Name and Technology of the Approved Test

The FDA-approved test is the Lumipulse G pTau217/Beta-Amyloid 1-42 Plasma Ratio test. Developed by Fujirebio Diagnostics, it works by calculating the ratio of pTau217 and beta-amyloid 1-42 proteins in blood plasmato predict the presence of amyloid plaques in the brain.

This biomarker ratio correlates strongly with amyloid accumulation, considered one of the biological signatures of Alzheimer's disease.

What Do the Scientific Data Show?

In approving this test, the FDA evaluated plasma samples from 499 individuals with suspected cognitive impairment in a multicenter clinical study. The striking findings were as follows:

• In 91.7% of individuals with a positive test result, PET scanning or CSF testing confirmed amyloid plaques.
• In 97.3% of individuals with a negative result, PET or CSF testing confirmed amyloid negativity.
• The indeterminate-result rate was low: fewer than 1 in 5 patients (approximately less than 20%) received an indeterminate result.

These results indicate that the test has high specificity (97.3%) and sensitivity (91.7%) .

An Alternative to PET and CSF Testing, but Not a Complete Replacement

The new Lumipulse blood test is recommended particularly for:

• People showing signs of cognitive decline,

• Adults aged 55 and older,

• Patients attending specialist centers, such as neurology services.

However, caution is needed: this test is not designed for screening and is not a standalone diagnostic tool. It should be used together with clinical history and other neuropsychological assessments.

What Has Changed? How Does It Differ From the Earlier Version?

In 2022, the FDA approved another Fujirebio test, the Lumipulse G Beta-Amyloid Ratio (1-42/1-40) test. However, that test required a cerebrospinal fluid (CSF) sample .

The main advantage of the new test:

It requires only a simple blood sample — making it more accessible and less invasive for patients.

Why Does It Matter? Disease Burden and Future Projections

• As of 024, approximately 700000 people in Turkey were living with Alzheimer's disease. By 2050, this number is expected to reach 1.6 million. The prevalence of Alzheimer's in people aged 65 and older is 5.5%.

• Worldwide, as of 2024, more than 55 million people have Alzheimer's disease. This number is projected to reach, in 2030, 78 million, and in 2050, 139 million . Approximately 10 million new cases of dementia are diagnosed each year.

• In the US, approximately 7 million people have Alzheimer's . This number is expected to reach 13 million in 2050 . 1 in every 10 people older than 65 is known to live with Alzheimer's . In the US, Alzheimer's affects more people than breast and prostate cancer combined.

Alzheimer's disease affects a vast number of people, and innovative diagnostic tools such as this test may enable earlier and more effective intervention.

Conclusion and Next Steps

The FDA granted the Lumipulse blood test “breakthrough device” status. It has the potential to help identify Alzheimer's at earlier stages and transform the journey for both patients and caregivers.

However, the test must be used with a neurologist and alongside other clinical assessments .

Summary:

• The first FDA-approved blood test for Alzheimer's

• High sensitivity and specificity

• Diagnostic support using only a blood sample

• An aid to clinical diagnosis, not a screening test

• For people older than 55 with signs of cognitive impairment