FDA approves first blood test to detect amyloid plaques linked to Alzheimer’s
The US Food and Drug Administration (FDA) has cleared the first blood test capable of detecting amyloid plaques, one of the key signs of Alzheimer’s disease, offering a simpler alternative to current diagnostic methods.
The test, which received FDA clearance on 16 May, is approved for people aged 55 and over who show signs or symptoms of Alzheimer’s.
It is reported to be more than 90 per cent accurate in detecting the disease.
Patients can now undergo the test via a standard blood draw ordered by a clinician.
Unlike PET scans or spinal fluid analysis — the current methods for detecting Alzheimer’s pathology — this approach is less invasive and potentially more accessible.
Dr Jeff Dage, senior research professor of neurology at Indiana University School of Medicine.
The researcher said: “This offers a less invasive, more accessible and scalable method to identify Alzheimer’s pathology early in the disease process.
“It opens the door to more efficient diagnosis, earlier interventions and broader participation in clinical trials, which is essential for advancing treatment.”
The test works by measuring the ratio of two proteins found in the brain and associated with Alzheimer’s: phosphorylated tau (pTau217) and β-amyloid 1-42.
These proteins filter into the bloodstream and serve as biomarkers — measurable biological indicators of disease.
Research that helped lead to the test’s development involved scientists from Indiana University School of Medicine, the Mayo Clinic, Lund University in Sweden, the University of San Francisco and Columbia University.
Between 2018 and 2020, the teams published key studies demonstrating the test’s accuracy — reporting a 96 per cent success rate in determining whether a patient had pathological signs of Alzheimer’s.
This performance was comparable to FDA-cleared cerebrospinal fluid testing and PET scans.
For nearly 15 years, doctors have used PET brain scans to detect amyloid plaques.
In 2022, the FDA cleared the use of lumbar punctures to collect cerebrospinal fluid for the same purpose.
However, both approaches are more invasive, more expensive, and less available to many patients compared to a blood-based alternative.
According to the Alzheimer’s Association, more than 7m people in the US are currently living with Alzheimer’s, with that number projected to rise to nearly 13m by 2050.
Dage said: “Now we can obtain more specific and accurate diagnoses of tens of thousands of patients and improve our understanding of the risk or protective factors specifically associated with Alzheimer’s disease or non-Alzheimer’s dementias.”
As the blood test is rolled out and clinicians become more familiar with its use, Dage believes it may support earlier diagnoses.
