I would personally want to know as early as possible, so I could get my affairs in order and register my wishes around end of life care and euthanasia while I am still recognised as having full mental capacity.

It's also better for people around the Alzheimer's patient, as it will let them understand why someone's personality and behaviours may be changing, and possibly let them be bit more forgiving of such changes. It will also give family more time to plan and understand the health and community services and support are offered wherever they live.

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 are (slightly) better than they were last year. That's a hell of a thing.

It's very useful to understand what you're struggling from even if it's not curable. It explains your symptoms, your experience and help you understand what you're going through. Understanding that you're suffering from something incurable is also helpful in not looking for other ineffective methods to cure a mysterious illness.

Most people get a dementia (or related) diagnosis after they are deep enough in it so that they cant do much about it or get their affairs in order.

My grandfather had a "fall" at work, he then left that job, and held down 2 more engineering jobs before he was diagnosed with a stroking condition and subsequent dementia. I got the distinct impression he thought he had more time, but rapidly declined.

If he knew he was short of time before his rapid decline he probably would have done things differently. Like not buying a house he would later have to sell to pay for aged care.

If he knew he was at risk of a workplace accident he probably wouldn't have worked as an after hours safety engineer at a major treatment plant, where if the worst had happened he could have endangered others.

> why we would want to detect Alzheimer’s

At a personal level, I've been through this with my grandfather.

I want to know. My family wants to know. I want to prepare because there are things I want to do today that I know I won't be able to do in the future.

In many ways, it's just like many terminal cancer diagnoses. You're going to lose that person, but you have some time.

The accuracy of this test is nowhere nearly good enough to do population-wide screening. The clinical setting for this test is memory clinics in which Alzheimers is already relatively highly likely differentially, and even there you're going to get a surprising number of false positives.

(There's enough info in the supplemental link on this page to have an LLM do the Bayes math for you.)

> doctors correctly diagnosed Alzheimer's in 75.5% of cases, but when incorporating blood test results, diagnostic accuracy increased to 94.5%

These patients are already seeing doctors. Would you rather your doctor to hide the diagnosis just because your disease isn't curable (for now)? It's not like we're testing the whole population in masse.

> 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.

Your point at the end is essentially correct. There's a couple of reasons that come to my mind:

Early detection lets us test cures more quickly. You can see if the treatment is working without waiting 30 years for symptoms to develop or not. If prevention is all that works, we can verify lifestyle changes, again without having to wait 30 years for symptoms to develop.

Early detection means there's more of a chance of any future treatment succeeding and the patient returning to a normal life. Think of early detection of cancer or heart disease meaning you can be treated with less risky medication and procedures and minimise the damage being done.

Being able to know someone's risk factor would be important for how we treat elderly people. I know someone who is 85 and super sharp (previously worked as a corporate accountant and banker), they still have a better memory than a lot of 40-50 year olds, and yet they are constantly harassed by eldercare "agents" for the state because whenever they make a investment decision that is even slightly questionable they get reported to the state by the bank. Sometimes the bank refuses to authorize transactions. If they could conclusively prove they aren't at risk I think they would be left alone much more often.

If the patient still has periods of lucidity but the disease is suspected to be advancing, knowing they have it could prompt them to get their legal affairs in order.

> 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.

Getting an accurate diagnosis is always important. Cognitive decline could be caused by other problems, some of which are more treatable than others.

If this test came back negative it would suggest extra testing to rule out other conditions like a brain tumor or hydrocephalus.

I assume this is hugely beneficial for research on intervention methods, not for treatment. I think everyone is focusing on "I'd rather know" but imagine if you could get larger populations with a diagnosis earlier on, how impactful that would be for testing an intervention?

there are treatments that can help slow progression, especially if it's found early.

the other big reason is clinical trials. if you can identify people who are pre-symptomatic but on a trajectory toward Alzheimer's, you can actually test whether early interventions work. that's been one of the big blockers for drug development -- by the time people show symptoms, they're often too far along for treatments to show effect. a reliable blood test changes the trial design fundamentally.

Having struggled with hard to diagnose health issues before, I can’t emphasize enough how much of a relief it is to put a name on the disease that is causing you so much harm.

It is frankly shocking to think disease diagnosis would be a useless thing

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.

For 20-ish% of Alzheimer's patients, the Shingles vaccine may be a treatment. This has been suspected for a few years now but has received recent confirmation studies.

https://www.alzheimers.org.uk/news/2025-11-18/promising-rese...

Even without a cure, there's still a lot of practical value in knowing earlier

This again?

The test is optional. Feel free to skip it.

Tell 50 million people they’re likely to have Alzheimer’s then tell them where to donate towards a cure, or treatments to slow it by a decade.

> For a disease which (to my knowledge) can’t be slowed down or reversed

There's Lecanemab and Donanemab. The effects are modest however.

This disease is in my family, honestly not sure I would want to know if I will get it.

If a loved one is suffering from this, this diagnostic would allow for interventions such as guardianship to assume financial and logistical responsibility for them with less subjective decisioning based on observations alone.

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.

There are more personal practical reasons too.

Even though it cannot be reversed or eradicated (yet, let's hope) detection can allow individuals to adopt interventions that help either adjust their lives to better cope with its progression or help mitigate some of the detrimental behavioral consequences. In addition, if you have family to care for it may be impetus to get certain things in order for them before later stages of the disease, etc. It's horrible and bleak, but I could certainly see why one might want to know.

In the lucky case, it can also relieve anxiety. Even though false negatives may still be possible, receiving a negative detection might give people who have anxiety about certain symptoms relief, since they can rule out (rightly or wrongly) a pretty severe disease.

Well, the AI CEOs are telling we will have AGI in ~5 years, so with millions of agents with AGI this thing should be sorted soon ;)