FDA Clears New Blood Test to Help Identify Signs of Alzheimer’s Disease

A new blood test designed to help doctors identify biological signs associated with Alzheimer’s disease has been cleared by the U.S. Food and Drug Administration, potentially making assessment of the condition simpler and more widely accessible.

The Elecsys pTau217 test, developed by Roche in collaboration with Eli Lilly, is intended for people aged 55 and over who are experiencing signs, symptoms or concerns relating to cognitive decline. It measures a protein known as phosphorylated tau 217, or pTau217, which is associated with amyloid changes in the brain linked to Alzheimer’s disease.

Unlike traditional methods used to identify amyloid pathology, which can involve PET brain scans or testing cerebrospinal fluid obtained through a lumbar puncture, the new test requires a routine blood sample. It can indicate whether a patient has a high or low likelihood of amyloid pathology, while an intermediate result may indicate that further investigation is needed.

Importantly, the test does not diagnose Alzheimer’s on its own. Roche says results should be considered alongside a patient’s symptoms, medical history and other clinical information as part of the wider diagnostic process.

The test could nevertheless make Alzheimer’s assessment considerably more accessible. It can be run on more than 4,500 existing Roche laboratory analysers across the United States, while major laboratory networks Labcorp and Quest Diagnostics have said they plan to offer it.

The development forms part of a wider shift towards blood-based testing for Alzheimer’s disease. In May 2025, the FDA cleared the first blood test designed to assist with Alzheimer’s diagnosis, and further tests have since emerged as researchers and healthcare systems look for less invasive ways to identify the disease earlier.

For patients and families, easier access to testing could help shorten what can currently be a lengthy and uncertain route to diagnosis, while allowing doctors to identify more quickly who may need specialist assessment or further testing.

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