FDA Approves First Blood Test for Alzheimer’s Diagnosis Starting at Age 40

The U.S. Food and Drug Administration (FDA) has approved PrecivityAD2, a new blood test designed to assist doctors in diagnosing Alzheimer’s disease in adults aged 40 and older who exhibit symptoms such as memory loss or cognitive decline. This marks the first blood test authorized for use in this younger age group, compared to the previous test approved last year for individuals aged 55 and above. The test is not intended for general population screening or asymptomatic individuals and cannot diagnose Alzheimer’s on its own; it is meant to be used alongside medical evaluations and additional tests.

Developed by C2N Diagnostics, a company founded at Washington University in St. Louis, PrecivityAD2 measures proteins linked to Alzheimer’s, including various forms of beta-amyloid and tau proteins, using high-resolution mass spectrometry. The test generates a score from 0 to 100 estimating the likelihood of amyloid plaque deposits in the brain. Clinical trials involving 1,142 participants with cognitive symptoms showed a 97.6% accuracy in detecting amyloid plaques when the test was positive, and 93.1% accuracy when negative, compared to PET scans or cerebrospinal fluid biomarkers.

Dr. Talia Natan, a senior neurologist at Ichilov Medical Center, highlighted the test as a significant advancement that could revolutionize the diagnosis and management of neurodegenerative diseases by providing a less invasive and more accessible alternative to lumbar punctures and PET scans. Early diagnosis is especially critical now with the availability of disease-modifying therapies (DMTs) that are more effective when started early.

The FDA approval is expected to expand access to this test in the U.S. later this year, potentially lowering costs through insurance coverage. While the availability date in Israel remains unclear, the test could facilitate earlier and more accurate diagnosis, enabling timely treatment and improved patient outcomes. The reduction in the diagnostic age threshold may also impact Alzheimer’s research by allowing larger and more diverse clinical trial participation.