Worried about Alzheimer’s? Diagnose Yourself

One third of healthy elderly will have a positive amyloid PET scan but will never show symptoms of dementia because they have adequate brain reserve. Higher educational level, working into old age, maintaining cognitive and social activities, and exercising all help to “preserve the reserve.” But two-thirds of those with a positive scan will be diagnosed with Alzheimer’s in 5–10 years. Distinguishing factors are imprecise.

Muddying these waters are the new direct-to-consumer Alzheimer’s blood tests which measure p-tau and are as accurate as the amyloid brain scan. In a recent survey, 75% of older adults would take the test. An abnormal result would prompt people to, say, retire sooner, downsize, travel more, and be nicer to their families. Another benefit is the opportunity to focus on end-of-life planning. The risk of suicide will probably prove to be low.

The most compelling reason not to do the p-tau blood test is the fact that we do not now have a disease modifying therapy for Alzheimer’s. This may change with a bang if Biogen’s anti-amyloid monoclonal antibody is approved by the FDA in the next few weeks. But the costs of this expensive medication, especially if asymptomatic people with a positive blood test demand treatment, may overwhelm our healthcare system.

Not only that. Medical testing companies are not obligated to maintain confidentiality. The data can be sold to a “third party.” If you have had it with invasions of your privacy, wait till you have a “positive” test. Insurers will refuse life, disability, and long-term care insurance. Employers may also discriminate. There is a great stigma of Alzheimer’s just as there is with epilepsy.

Knowledge is power but be careful what you wish for.

Adapted from the “Viewpoint” by Largent et al in JAMA Neurology, April 2021.

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