This Alzheimer's blood test, PrecivityAD2, is based on the p-tau217 biomarker.
In one recent study, people very high p-tau217 had a 38% chance of progressing to cognitive impairment within 5 years vs 12% for those with low levels. The current tests cost about $200-300, so they're not unreasonable as a screening test. PrecivityAD2 looks to be priced around $1,400-$1,500 so at that price, this specific test likely only makes sense for people with established disease.
We can also test for PSEN1, which is 100% accurate in determining early onset alzheimer's disease, quite a it more expensive, so unreasonable as a screening tool unfortunately.
That sounds pretty expensive for me for a test with that low accuracy, especially when there's not much you can do different if it comes back high vs. coming back low.
> Early detection of Alzheimer’s disease is important since the first treatments capable of slowing the progression of the neurodegenerative disease recently became available to patients, and these drugs are more effective when started sooner rather than later. Other promising investigational drugs are in the pipeline.
A very good friend's wife had Alzheimer's caught early, and the medication she's on stopped its progression. It's much better for her than my family members who had no treatment options.
Agreed that we can't do as much as we'd like. There are some general health things that are believed to prevent cognitive decline, such as managing cholesterol, HbA1c, blood pressure, sleep apnea, etc. One phrase I've heard is that cholesterol at age 50 predicts cognitive health at age 70.
But hopefully we'll start to have more options and wider approvals for things like anti-amyloid drugs.
That price difference seems like the key point. A $200 test can plausibly be used to decide who should get further workup; a $1500 test is already competing with the cost of the workup itself
From a medical perspective, what's the point of the initial test or the workup though? Is it just to check a box? If it comes back positive you will be told to exercise, eat well, take sleep seriously, and manage cholesterol. If it comes back negative you will be told to do the same things.
I've seen up close what dying with these kinds of illnesses look like. For me, a positive test would be a sign that it may be time to say my goodbyes and plan my exit.
Do we yet have any good avoidance or mitigation regimes, be they drug or otherwise for people who show positive on a test like this? The alternative is that it lets you put things in place for when you lose agency.
Good as in scientifically proven. Not speculative fantasy.
We don’t currently have any data that shows any clear way to halt or slow Alzheimer’s.
As someone with family affected by this disease, it’s a very personal choice whether you want to know or not, but I wish people understood that there are many things you can do with it, particularly for those who will be there for you if/when it hits.
Taking care of a loved one with this disease is extremely hard, and it’s even harder when they haven’t had any chance to prepare for this eventuality. Stuff like written records of your history (health, life, etc.), clear powers of attorney, and so on.
It also makes things much easier for healthcare professionals.
Just lost my aunt to Alzheimer's this last week. +1 on the hard to take care of bit. They turn into toddlers, then animals, then nothing. It's heartbreaking.
One other piece of advice I would offer is: find a class at your local hospital or similar. I attended a once-a-week for six weeks thing and it made a huge difference in my perception of dealing with someone suffering from dementia and gave me so much more patience/ grace than I would have had otherwise.
The article doesn't explicitly say but presumably you can start taking the anti-amyloid drugs to slow down the progression immediately, there's also lifestyle changes that can be made (most of those would likely benefit most people)
> Early detection of Alzheimer’s disease is important since the first treatments capable of slowing the progression of the neurodegenerative disease recently became available to patients, and these drugs are more effective when started sooner rather than later.
Not a doctor or medical scientist, but my understanding is a) the effectiveness of those anti-amyloid drugs as a preventative tool is unclear, and b) they have a pretty scary safety profile.
Clearly the goal is to be able to prevent the disease from progressing or slow it significantly, but are we really there yet even if we have a test?
Yes, there is the FINGERS method. See e.g. https://fbhi.se
For Alzheimer is particular, there are also some drugs now (e.g. Leqembi) that slow down the process, but no cure yet.
If this gets cheap enough and the predictive values hold up in ordinary clinical populations, it could change when people actually get evaluated rather than just how they get evaluated
Because tests aren't completely innocuous? Because tests lead people to make significant medical decisions?
Look at the supplements world, where grifters are shilling chemicals that cause harm and make radical claims for absurd markups. Or gas station pills. You want those companies making Alzheimer's tests? People going in to a 7-11 and buying a "all illness test card" that tells people they do or don't have degenerative diseases?
No, it's very very important to ensure tests are actually indicative and ensure they are well made. To do that, a regulating body needs to be involved.
Their doctor should be qualified to make that judgment without a government bureaucracy evaluating the efficacy of the test on their behalf, unless you want to completely destroy the rate of medical breakthroughs. If there's no potential harm from the procedure itself, the government shouldn't be involved at all.
Imagine if every new AI model had to be "cleared" by a government regulator. The role of government in healthcare evaluation needs to be simplified and streamlined. The liability needs to be shifted to doctor, and if it's a case of charlatanism, that liability should include a lengthy prison sentence.
I think you need FDA clearance to be able to market a test as actually being effective for treatment/prevention etc. For exactly the same reason woo-woo supplements must disclaim that they aren't intended for that purpose
These tests are more or less useless because there's no treatment anyway so knowing about it a long time in advance will not lead to any substantial gain. Even slowing the disease isn't within the realm of today's technology. Today's pharmaceutical companies are close to quacks as far as Alzheimer is concerned. We know next to nothing about its origins or even how the disease progresses.
The only thing you gain is giving people more time to worry and despair.
Earlier diagnosis, or at least suspected diagnosis, could make a difference in studying progression, origin, etc.
Imagine the test is 100% accurate: if you gave it to a group of people, you could then try to make interventions earlier, capture more data about lifestyle before symptoms, etc.
Patients becoming involuntary guinea-pigs for science? No thanks.
As long as there isn't a clear root cause found and some real mitigating medicines reach the market I would propose keeping people ignorant as long as we can.
This is an infuriatingly clueless comment. It gives nothing? It allows people to set their affairs in order, and that is an invaluable thing.
Alzheimers can lead to all kinds of other issues like impulsivity, or aggressiveness. People gambling away their life savings, not knowing that they are even doing it. Doctors unable to intervene due to rights around patient autonomy. All of this has big consequences in the lives of those affected.
These tests are not useless, but I’d agree (from personal experience) that it’s far from clear that everyone should take one.
There’s a degenerative genetic disease that runs in my family that for various reasons we only found out about ten years ago. To get the test done in the UK for it, you have to go to mandatory genetic counselling where they try to convince you not to get it done. Of four siblings, the two of us who thought initially we’d definitely get it done, we’ve not, and the two who were sure they wouldn’t, have done.
They try and convince you not to get it done so you don’t end up confusing being tired one morning or tripping with “oh my God it’s starting”.
Everyone should get their affairs in order, regularly, without needing a test, if they care about their loved ones.
This Alzheimer's blood test, PrecivityAD2, is based on the p-tau217 biomarker.
In one recent study, people very high p-tau217 had a 38% chance of progressing to cognitive impairment within 5 years vs 12% for those with low levels. The current tests cost about $200-300, so they're not unreasonable as a screening test. PrecivityAD2 looks to be priced around $1,400-$1,500 so at that price, this specific test likely only makes sense for people with established disease.
We can also test for PSEN1, which is 100% accurate in determining early onset alzheimer's disease, quite a it more expensive, so unreasonable as a screening tool unfortunately.
That sounds pretty expensive for me for a test with that low accuracy, especially when there's not much you can do different if it comes back high vs. coming back low.
From TFA:
> Early detection of Alzheimer’s disease is important since the first treatments capable of slowing the progression of the neurodegenerative disease recently became available to patients, and these drugs are more effective when started sooner rather than later. Other promising investigational drugs are in the pipeline.
A very good friend's wife had Alzheimer's caught early, and the medication she's on stopped its progression. It's much better for her than my family members who had no treatment options.
5 replies →
Agreed that we can't do as much as we'd like. There are some general health things that are believed to prevent cognitive decline, such as managing cholesterol, HbA1c, blood pressure, sleep apnea, etc. One phrase I've heard is that cholesterol at age 50 predicts cognitive health at age 70.
But hopefully we'll start to have more options and wider approvals for things like anti-amyloid drugs.
8 replies →
I guess you can start spending your retirement money faster
2 replies →
That price difference seems like the key point. A $200 test can plausibly be used to decide who should get further workup; a $1500 test is already competing with the cost of the workup itself
From a medical perspective, what's the point of the initial test or the workup though? Is it just to check a box? If it comes back positive you will be told to exercise, eat well, take sleep seriously, and manage cholesterol. If it comes back negative you will be told to do the same things.
I've seen up close what dying with these kinds of illnesses look like. For me, a positive test would be a sign that it may be time to say my goodbyes and plan my exit.
1 reply →
epistemics asks how many different hypotheses besides p-tau217 levels were tested before arriving at the specified spread.
Are you suggesting that these research scientists don't understand basic statistics?
1 reply →
Seems like a no brainer for hetero/homozygous APOE4 folks.
do you have the reference for that one? I'd be interested in reading it.
Sure! The study is from July 2026: https://jamanetwork.com/journals/jama/fullarticle/2851720
1 reply →
Do we yet have any good avoidance or mitigation regimes, be they drug or otherwise for people who show positive on a test like this? The alternative is that it lets you put things in place for when you lose agency.
Good as in scientifically proven. Not speculative fantasy.
We don’t currently have any data that shows any clear way to halt or slow Alzheimer’s.
As someone with family affected by this disease, it’s a very personal choice whether you want to know or not, but I wish people understood that there are many things you can do with it, particularly for those who will be there for you if/when it hits.
Taking care of a loved one with this disease is extremely hard, and it’s even harder when they haven’t had any chance to prepare for this eventuality. Stuff like written records of your history (health, life, etc.), clear powers of attorney, and so on.
It also makes things much easier for healthcare professionals.
Just lost my aunt to Alzheimer's this last week. +1 on the hard to take care of bit. They turn into toddlers, then animals, then nothing. It's heartbreaking.
2 replies →
One other piece of advice I would offer is: find a class at your local hospital or similar. I attended a once-a-week for six weeks thing and it made a huge difference in my perception of dealing with someone suffering from dementia and gave me so much more patience/ grace than I would have had otherwise.
1 reply →
Not true!
https://www.harvardmagazine.com/2025/05/harvard-taxi-drivers...
For some reason, taxi drivers seem to have a dramatically lower risk of it.
3 replies →
The article doesn't explicitly say but presumably you can start taking the anti-amyloid drugs to slow down the progression immediately, there's also lifestyle changes that can be made (most of those would likely benefit most people)
https://www.nih.gov/news-events/news-releases/combination-he...
> Early detection of Alzheimer’s disease is important since the first treatments capable of slowing the progression of the neurodegenerative disease recently became available to patients, and these drugs are more effective when started sooner rather than later.
Not a doctor or medical scientist, but my understanding is a) the effectiveness of those anti-amyloid drugs as a preventative tool is unclear, and b) they have a pretty scary safety profile.
Clearly the goal is to be able to prevent the disease from progressing or slow it significantly, but are we really there yet even if we have a test?
1 reply →
Yes, there is the FINGERS method. See e.g. https://fbhi.se For Alzheimer is particular, there are also some drugs now (e.g. Leqembi) that slow down the process, but no cure yet.
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If this gets cheap enough and the predictive values hold up in ordinary clinical populations, it could change when people actually get evaluated rather than just how they get evaluated
Why is the FDA "clearing" something that is completely innocuous like a blood test?
Google "what did theranos do" to find out why.
Because tests aren't completely innocuous? Because tests lead people to make significant medical decisions?
Look at the supplements world, where grifters are shilling chemicals that cause harm and make radical claims for absurd markups. Or gas station pills. You want those companies making Alzheimer's tests? People going in to a 7-11 and buying a "all illness test card" that tells people they do or don't have degenerative diseases?
No, it's very very important to ensure tests are actually indicative and ensure they are well made. To do that, a regulating body needs to be involved.
Their doctor should be qualified to make that judgment without a government bureaucracy evaluating the efficacy of the test on their behalf, unless you want to completely destroy the rate of medical breakthroughs. If there's no potential harm from the procedure itself, the government shouldn't be involved at all.
Imagine if every new AI model had to be "cleared" by a government regulator. The role of government in healthcare evaluation needs to be simplified and streamlined. The liability needs to be shifted to doctor, and if it's a case of charlatanism, that liability should include a lengthy prison sentence.
3 replies →
I think you need FDA clearance to be able to market a test as actually being effective for treatment/prevention etc. For exactly the same reason woo-woo supplements must disclaim that they aren't intended for that purpose
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These tests are more or less useless because there's no treatment anyway so knowing about it a long time in advance will not lead to any substantial gain. Even slowing the disease isn't within the realm of today's technology. Today's pharmaceutical companies are close to quacks as far as Alzheimer is concerned. We know next to nothing about its origins or even how the disease progresses.
The only thing you gain is giving people more time to worry and despair.
Earlier diagnosis, or at least suspected diagnosis, could make a difference in studying progression, origin, etc.
Imagine the test is 100% accurate: if you gave it to a group of people, you could then try to make interventions earlier, capture more data about lifestyle before symptoms, etc.
Patients becoming involuntary guinea-pigs for science? No thanks.
As long as there isn't a clear root cause found and some real mitigating medicines reach the market I would propose keeping people ignorant as long as we can.
I think I'd want to know.
It would affect my financial and estate planning, and how I'd like to navigate the disease's progression.
This is an infuriatingly clueless comment. It gives nothing? It allows people to set their affairs in order, and that is an invaluable thing.
Alzheimers can lead to all kinds of other issues like impulsivity, or aggressiveness. People gambling away their life savings, not knowing that they are even doing it. Doctors unable to intervene due to rights around patient autonomy. All of this has big consequences in the lives of those affected.
When the symptons set on you'll have plenty of time to wind down your affairs.
These tests are not useless, but I’d agree (from personal experience) that it’s far from clear that everyone should take one.
There’s a degenerative genetic disease that runs in my family that for various reasons we only found out about ten years ago. To get the test done in the UK for it, you have to go to mandatory genetic counselling where they try to convince you not to get it done. Of four siblings, the two of us who thought initially we’d definitely get it done, we’ve not, and the two who were sure they wouldn’t, have done.
They try and convince you not to get it done so you don’t end up confusing being tired one morning or tripping with “oh my God it’s starting”.
Everyone should get their affairs in order, regularly, without needing a test, if they care about their loved ones.