Blood Test for Alzheimer

[Jaque]

Palmqvist S, Janelidze S, Quiroz YT, et al. Discriminative Accuracy of Plasma Phospho-tau217 for Alzheimer Disease vs Other Neurodegenerative Disorders. JAMA. Published online July 28, 2020. doi:10.1001/jama.2020.12134

https://www.nytimes.com/2020/07/28/heal ... -test.html

[hairyfairy]

Why would anyone want such a test. I most definitely wouldn`t want to know if I was going to develop AD because there`s no cure.

[NF52]

Why would anyone want such a test. I most definitely wouldn`t want to know if I was going to develop AD because there`s no cure.

Welcome back, hairyfairy! You raise a great question BUT...the news headlines got it wrong! Biomarkers do not equal Alzheimer's dementia. They only equal "early stages of changes that in 15-20 years could lead to dementia".

About 40% of people in their 90's whose brains show amyloid beta and tau after death NEVER showed any sign of cognitive impairment. Between 40-60% of people with ApoE 4/4 are NEVER diagnosed with Alzheimer's dementia before the age of 85 (the average lifespan in the US and Europe).

So knowing you have amyloid beta or tau in the brain does NOT mean you have a diagnosis of Alzheimer's dementa; it means you have a diagnosis of signs of Alzheimer's "disease" in your brain--and maybe 15-20 years to prevent Alzheimer's dementia. For now, this also means that drugs that seek to reduce amyloid beta, or tau, or protect your synapses. could be especially important for you.
And researchers want to find these people, because some earlier studies, that assumed everyone with a diagnosis of "Alzheimer's" actually had Alzheimer's disease in their brain found out in later PET scans that up to 1/3 DID NOT!! Imagine if we spent money studying drugs to cure breast cancer before we had a good way to diagnose breast cancer--so that we included 1/3 of people who didn't have the disease!

Here's my take-away, which I shared with my sister, who said exactly what you said: "Once there is an effective treatment for those people who may be facing a diagnosis of Mild Cognitive Impairment within 7-10 years no matter how good their exercise, diet, etc., then I think it will be time to take that test--and that could be within the next 5 years."