Closer To A Blood Test For Alzheimer’s

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Clumps of amyloid beta can begin building up in the brains of Alzheimer’s sufferers nearly 20 years before the individuals exhibit the memory loss and confusion characteristic of Alzheimer’s disease. Currently, the most reliable method of detecting amyloid beta buildup before exhibition of behavioral symptoms is using a PET scan (Positron emission tomography) (Brain Scans Prevent Alzheimer’s Misdiagnosis and Lead to Better Treatment—But They’re Not Covered By Medicare), but these are expensive, not covered by insurance, and take time and a visit to a site with the right scanning machinery. Because of this, few people have the scans done on a routine annual basis, and it is very difficult for drug researchers to recruit participants who might develop Alzheimer’s in the future, but don’t current exhibit memory loss and confusion.

These are all reasons why a blood test which could detect buildup of amyloid beta as early as PET scans would be highly desirable. A recent research publication reports on work coming very close to such a test. A certain amount of amyloid beta is naturally present in both brain and blood. The test first chops up the amyloid obtained from a blood sample with enzymes. The amounts of two fragments, called a-beta 42 and a-beta 40, are obtained by mass spectrometry, and their ratio is computed. As amyloid beta starts building up in the brain, less of the fragment a-beta 42 is available for circulation in the blood, and so the computed ratio goes down. Utilizing this ratio, together with an individual’s age and genetic risk, the test was able to match PET scan performance on 94% of the study participants.

Although at present there are no reliable methods of treating Alzheimer’s, a positive result on a blood test such as this would enable one to take steps to defer the onset of the disease, using:

And, sensibly, one could ensure that one’s will and healthcare advance directive were up to date, and one could consider creating an Advance Directive for Dementia.

Here are three media articles on the blood test work:
Blood test can identify Alzheimer’s 2 decades before symptoms
Blood test is 94% accurate at identifying early Alzheimer’s disease
New Alzheimer’s Blood Test Proved 94% Accurate in Finding Brain Changes Related to the Disease

Here is the published research article:
High-precision plasma β-amyloid 42/40 predicts current and future brain amyloidosis

All links have been added to Alzheimers > Diagnosis & Tests