11/17/2025
You may have heard about a new blood test for Alzheimer’s disease that recently received FDA clearance. Alzheimer’s is a progressive brain disorder that affects memory, thinking, and behavior. It is one of several causes of dementia, a broad term describing decline in cognitive abilities severe enough to interfere with daily life. Other forms of dementia include vascular dementia, Lewy body dementia, frontotemporal dementia, and mixed types, which often overlap. Alzheimer’s stands out because of the characteristic buildup of abnormal proteins in the brain, called amyloid and tau, that damage and destroy nerve cells over time.
The new test, called Elecsys pTau181 (pronounced ee-LEK-sis pee-tow one-eighty-one), measures a specific form of the tau protein in the blood that tends to increase when Alzheimer’s-type changes are present in the brain. It is approved for adults aged 55 and older who have symptoms or concerns about cognitive decline. The test’s main role is to help rule out Alzheimer’s-related pathology in primary care. If the test result is negative, it strongly suggests that Alzheimer’s is not the main cause of symptoms. However, a positive result does not confirm the diagnosis on its own. Further testing, such as imaging or spinal fluid studies, is still needed for certainty. The goal is to give clinicians an earlier, less invasive way to decide who might need additional evaluation or referral to a neurologist.
For those who do have Alzheimer’s-type disease, treatment options have evolved. The long-standing medications, including donepezil, rivastigmine, galantamine, and memantine, help with symptoms like memory or focus but do not stop the disease itself. In the past few years, new therapies have emerged that target the buildup of amyloid plaques directly. These are monoclonal antibody infusions such as lecanemab (leh-KAN-eh-mab, brand name Leqembi) and donanemab (doh-NAN-eh-mab, brand name Kisunla), designed to clear amyloid from the brain. Clinical trials suggest that these medications can slow cognitive decline by roughly 25 to 35 percent over 18 months in patients with early Alzheimer’s disease, which is meaningful but not curative. They also require careful monitoring because of potential side effects like brain swelling or bleeding.
Cost remains another consideration. These drugs are priced around $25,000 to $30,000 per year, not including infusion and monitoring costs. They are typically reserved for patients in the earliest stages of the disease, confirmed through biomarker testing or imaging. For now, these therapies represent an important step toward disease-modifying treatment, but they are not a cure and their benefits vary between individuals.
This new blood test may eventually help more patients and families identify the cause of memory loss earlier and discuss options sooner. But it is still just one piece of a larger diagnostic puzzle. As always, evaluation and treatment decisions should be made with your physician based on your full clinical picture and personal goals.
Disclaimer: This article is for general informational purposes only and is not medical advice. Please consult your healthcare provider for individualized guidance.
https://www.fiercebiotech.com/medtech/roche-nabs-fda-clearance-alzheimers-biomarker-blood-test
