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Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

medicalxpress.com

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Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#51

Post by janeway »

“We have no cure. I don’t want to know.”

If astronomers announced that a large asteroid might strike Earth in twenty years, and that we currently had no way to deflect it, nobody would respond by saying, “Come back when you already have the rocket.” We would immediately build better telescopes to track it precisely, refine its trajectory models, and begin developing propulsion systems capable of interception. You do not wait for the cure before improving the measurement. You improve the measurement so that a cure becomes possible, targeted, and effective.

Medicine is no different. Refusing to improve early, probabilistic diagnosis because today’s treatments are modest confuses sequence with outcome. Breakthroughs do not emerge from vague labels and mixed populations. They emerge from precise, quantitative stratification that allows real effects to be seen. The danger is not that we measure too early. It is that we continue making irreversible clinical and research decisions using imprecise, binary classifications while biological insight and therapeutic tools are advancing rapidly. Building the probabilistic layer now is not premature. It is how we make future intervention feasible.

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#52

Post by ChadNauseam »

Baeocystin wrote: post #14
janalsncm wrote: post #4

For a disease which (to my knowledge) can’t be slowed down or reversed, I think it’s a fair question why we would want to detect Alzheimer’s. Maybe there are other reasons, but my suspicion is that we will be able to, and an easy detection method significantly widens the pool of subjects to study later on. If it turns out that driving a Prius on Tuesdays slows down Alzheimer’s, a larger pool of subjects would allow u…

I know two people who have been taking the new monoclonal antibody treatment for it. One who was a bit further along when she started, and did not show any significant improvement. The one who started while she was still in the early stages has completely arrested her descent. She hasn't recovered much of what she already lost, but she's still able to live independently and enjoy life, and her mental acuity scores ar…

I also know someone who's significantly better now than they were a few years ago thanks to alzheimer's medication. And Trontinemab, which is currently in phase III trials I believe, seems even better than what is publicly available as it crosses the blood-brain barrier more readily. We're entering a brighter future for alzheimer's patients.

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#53

Post by aix1 »

refurb wrote: post #22

94.5% is actually terrible. If you have a prevalence of 10 in 1000, how do the numbers shake out? Well, you test all 1,000. If we assume a 95% accuracy for false-positive and false negatives? Of the 990 that you test that don't have the disease, the test will false state 50 do have the disease. Yikes! And of the 10 that do have the disease? You'll miss 1 of them.

> 94.5% is actually terrible.

This statement is quite broad and misses several important factors.

First of all, a test's sensitivity and specificity. The math in your example assumes a balanced test, but on what basis? The math comes out quite different for high-sensitivity or high-specificity tests. (Unfortunately, I could not find the numbers for the test in the linked article.)

Secondly, whom are we testing? The prevalence rate in your example (1%) is unrealistically low even for the general population. But would we screen the general population? No, we'd screen high-risk groups: the elderly, those with certain APOE genotypes etc. Predictive values of a test depend hugely on the prevalence rate.

Lastly, it depends on how the results are used. If it's a high-sensitivity test used to decide whom to send to the next tier in a multi-tier diagnostic system, it could actually be quite effective at that (very rarely missing the disease while greatly reducing the need for more expensive or more invasive testing).

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#54

Post by ChadNauseam »

redox99 wrote: post #33
janalsncm wrote: post #4

For a disease which (to my knowledge) can’t be slowed down or reversed, I think it’s a fair question why we would want to detect Alzheimer’s. Maybe there are other reasons, but my suspicion is that we will be able to, and an easy detection method significantly widens the pool of subjects to study later on. If it turns out that driving a Prius on Tuesdays slows down Alzheimer’s, a larger pool of subjects would allow u…

> For a disease which (to my knowledge) can’t be slowed down or reversed There's Lecanemab and Donanemab. The effects are modest however.

Trontinemab is in trials right now and has 92% of patients achieving low amyloid levels. And more people should be able to take it as it causes less brain swelling (ARIA-E). I'm unaffiliated, I just follow medical research in my free time. But I'm quite hopeful about this medication

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#56

Post by Mathnerd314 »

dzink wrote: post #18

This needs to include life-changing false positive rates. Imagine being given a diagnosis like this - people around you who know and any corporations who can sniff it out by snooping on your communications can lead to much rejection early in life. What happens when the diagnosis is as positive when it shouldn’t have been?

https://doi.org/10.1038/s41591-025-03622-w this is the paper they're basing the research on. So in primary care, the accuracy rates are in the 80s. So that's something like a 17% false positive rate. That's still like 5 to 1 odds of getting a correct result though. It's much better than nothing.

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#57

Post by shevy-java »

janalsncm wrote: post #4

For a disease which (to my knowledge) can’t be slowed down or reversed, I think it’s a fair question why we would want to detect Alzheimer’s. Maybe there are other reasons, but my suspicion is that we will be able to, and an easy detection method significantly widens the pool of subjects to study later on. If it turns out that driving a Prius on Tuesdays slows down Alzheimer’s, a larger pool of subjects would allow u…

I understand the "detect deadly progression but no cure" problem; this was the same rationale people used when Huntington disease could be verified in diagnostics. Many people don't want to know, but some want to know, in particular as you can manage some things here or there - diet affects many things, for instance, even aside from metaboic genetic defects. And for any (molecular) therapy at a later time you need to understand the molecular basis to some extent. Some things can be found out via trial and error (vaccination and before) but for some disease that can not work. Alzheimer is quite complex.

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#58

Post by rossant »

janeway wrote: post #51

“We have no cure. I don’t want to know.” If astronomers announced that a large asteroid might strike Earth in twenty years, and that we currently had no way to deflect it, nobody would respond by saying, “Come back when you already have the rocket.” We would immediately build better telescopes to track it precisely, refine its trajectory models, and begin developing propulsion systems capable of interception. You do…

I agree. I feel that many medical doctors do not share this mindset.

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#59

Post by eshack94 »

janalsncm wrote: post #4

For a disease which (to my knowledge) can’t be slowed down or reversed, I think it’s a fair question why we would want to detect Alzheimer’s. Maybe there are other reasons, but my suspicion is that we will be able to, and an easy detection method significantly widens the pool of subjects to study later on. If it turns out that driving a Prius on Tuesdays slows down Alzheimer’s, a larger pool of subjects would allow u…

Not saying anything about the article at-hand, but assuming we were able to detect it with such certainty, I think it would greatly increase the funding, rigor, and breadth or research devoted to finding a cure or treatment that actually worked.

Re: Blood test boosts Alzheimer's diagnosis accuracy to 94.5%, clinical study shows

#60

Post by jader201 »

janeway wrote: post #51

“We have no cure. I don’t want to know.” If astronomers announced that a large asteroid might strike Earth in twenty years, and that we currently had no way to deflect it, nobody would respond by saying, “Come back when you already have the rocket.” We would immediately build better telescopes to track it precisely, refine its trajectory models, and begin developing propulsion systems capable of interception. You do…

> “We have no cure. I don’t want to know.”

> If astronomers announced that a large asteroid might strike Earth in twenty years, and that we currently had no way to deflect it, nobody would respond by saying, “Come back when you already have the rocket.”

I don’t think the analogy fits, for a couple reasons.

1. People not wanting to know whether they have Alzheimer’s is because of the fear of a fate worse than death — living with Alzheimer’s.

2. People not wanting to know whether they have Alzheimer’s is not the same was not wanting a way to detect it. As you said, being able to measure it may help lead to a cure/treatment. I doubt people are against improving detection — they may just not want the detection to be applied personally.

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