FDA Approves First Blood-Based Alzheimer’s Test for Early Detection

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For the first time, a simple blood test can help doctors in primary care settings rule out Alzheimer’s disease in people showing early signs of memory loss or confusion. The new Elecsys pTau181 test, developed by Roche in collaboration with Eli Lilly, was cleared by the U.S. Food and Drug Administration (FDA) on October 13, 2025. It’s the first blood-based biomarker test approved to aid in the initial assessment of Alzheimer’s disease and other causes of cognitive decline.

The test measures levels of phosphorylated tau (pTau181) — a protein linked to Alzheimer’s-related changes in the brain. When combined with other clinical information, results can help doctors identify patients who are unlikely to have Alzheimer’s pathology, reducing unnecessary anxiety, specialist visits and costly procedures.

Until now, Alzheimer’s — a condition that currently affects more than 7 million Americans — biomarker testing was only available through invasive spinal taps or expensive brain scans, often ordered by neurologists. The Elecsys pTau181 test changes that. It can be done with a simple blood draw and run on Roche’s widely used laboratory instruments, which are already installed in more than 4,500 U.S. clinical labs. This makes it much easier for primary care doctors to incorporate Alzheimer’s screening into routine evaluations for adults aged 55 and older who report memory changes or cognitive symptoms.

In a clinical study involving 312 participants, the Elecsys pTau181 test showed a 97.9% accuracy in ruling out Alzheimer’s pathology in early-stage patients — a significant milestone in improving diagnostic efficiency. With broader use in primary care, it could help ensure that neurologists and specialists focus on the patients most likely to need advanced evaluation and treatment.

This test also has the potential to reduce the use of more invasive and costly diagnostic tools, such as positron emission tomography (PET) scans and cerebrospinal fluid testing. By helping identify which patients do not show Alzheimer’s-related changes, the Elecsys pTau181 test may shorten diagnostic delays, lower health care costs and provide peace of mind for patients and families.

Roche’s broader Alzheimer’s portfolio — which includes both blood-based and cerebrospinal fluid tests — reflects a growing movement toward earlier, simpler and more accessible detection of neurological diseases. With FDA clearance in the U.S. and CE Mark certification in Europe, the Elecsys pTau181 test represents a new chapter in the global effort to bring timely, minimally invasive Alzheimer’s testing closer to patients.

“By bringing Alzheimer's blood-based biomarker testing into primary care, we can help patients and their clinicians get answers sooner to support them earlier in their journeys,” said Brad Moore, president and CEO of Roche Diagnostics North America, in a statement. “This milestone reflects Roche’s leadership in diagnostics and our commitment to expanding access to innovative testing for patients and their clinicians.”