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.
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.
I am not personally aware of any treatment for which there is particularly compelling evidence that it meaningfully slows progression even when started early. I wish there was.
It’s also not clear that one can measure progression well enough that an n=1 data point is meaningful. And I’m also far from convinced that very early Alzheimer’s that would progress rapidly enough to be noticeable can be detected with enough specificity to rule out fairly common cases of people who test positive but effectively don’t have the disease.
Best wishes to your friend’s wife.
The amyloid treatments slow cognitive decline by 35% or so for 18 months. Some papers argue (and I believe) the effect is small enough many patients don't notice or seem to benefit.
We shall see if yet another generation of amyloid-targeted treatment does any better. The amyloid-hypothesis boosters seem to think so - we had a thread about this not that long ago. But I remain skeptical.
Agreed that that it’s an interesting question on how to detect Alzheimer’s and also how to treat. My Dad is starting to show signs of mild mental impairment (he’s 87) - more forgetful than usual, more confused than usual, not able to work his computer like he used to…
He has taken a personal interest in preventing dementia and wants to take the first generation Alzheimer’s drugs, specifically leqembi that works on amyloid plaques. And this is definitely a tough choice, because eventhough it does show some slowing of the disease, it has lot of side effects that may not be worth it.
Personally, I am against it and don’t think it’s worth it as he could do permanent damage to himself. Think he should hang on until the second generation of drugs come out, which should be in the next 1-3 years (there a lot of Alz drugs in the pipeline, but you never know of course if anything will pan out). It’s a tough choice and don’t know if there is a good option at this point.
I'm sorry your dad is facing this disease. Hopefully he can find something that helps slow it. I don't know what the side-effects are that he could be facing but, as someone who lost a parent to alzheimers, let me say that anything is probably preferable to advanced-stage dementia. I hope to see real, reliable treatments in my lifetime.
Creatine supplementation is showing some promising indications of being a low cost, mild to moderate intervention https://www.psychologytoday.com/us/blog/the-modern-brain/202...
I definitely wouldn't be sharing that as evidence of anything much at all
Google scholar link for the article https://scholar.google.com/scholar?cluster=10296105574478709...
Whether this ends up being replicated or not, I love the classic gym bro supplement being studied for its potential benefits to the brain.
What a time to be alive
It's going to be replicated because we already know the mechanism of action. That said, many/most people would probably be better off solving the problem more upstream via whatever B-complex vitamins they need based on their bloodwork and DNA methylation variants.
> the medication she's on stopped its progression
what medication is that?
what? there aren't any treatments that stop alzheimers, there are some that help manage symptoms
May not completely stop it, but lecanemab and donanemab are certainly considered to be disease-progression modifying at this point.
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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.
Hi there. Actually, Leqembi is a 1st gen Alzheimer’s drugs and targets amyloid plaques. But, like other responses, amyloids doesn’t seem to be hugely responsible for Alzheimers, which is why targeting things like tau proteins is being explored.
> anti-amyloid drugs
Isn’t the viewpoint in the last decade that amyloid plaques are likely a finding rather than the underlying cause of Alzheimer’s Disease?
The "standard" theory is that amyloid leads to tau protein accumulation which leads to neurodegeneration: https://www.astralcodexten.com/p/in-defense-of-the-amyloid-h.... Which would explain why current treatments don't really work: by the time Alzheimer's has progressed to noticeable impairment there's already too much tau, so reducing amyloid will at best slow the rate of decline by reducing the formation of new tau.
> Which would explain why current treatments don't really work ... [they] at best slow the rate of decline
This is called working! I am struck by the double-standard applied to assessing treatment options for Alzheimer's vs cancers. Many (most?) Stage IV cancers are incurable, and the main goal of treatment is to slow progression of the disease. Adding years to patients' lives is absolutely worth it, assuming the side effects are not overwhelming and the costs are not prohibitive.
To wit: Moderna added ~30B to its market cap on the news that it observed _statistically significant_ improvement in its primary endpoint for treating metastatic melanoma. Great! I'm as excited about this development as anyone. A new treatment option for a terrible disease that meaningfully improves on the current standard of care (Keytruda). Sadly, Stage IV melanoma is still considered terminal, and no one suggested that Moderna changed that.
Why not reset expectations for Alzheimer's? If we manage to slow its development enough so that most patients (who tend to be elderly) would die of other causes while maintaining decent quality of life, that's a win in my book.
ever since the discovery of amyloid plaques, it's been an open question. Are they causative or a symptom? Would reducing or eliminating them help treat the disease? There is lots of data that supports amyloid as a disease treatment target, particularly in animal models. Of course the abject failure to actually develop a good anti-amyloid treatment that actually provable and significantly mitigates the disease weighs against the idea that amyloid is a good target. And the high profile frauds that have been discovered haven't helped. But, the biomedical community are not a bunch of morons. All these drug companies wouldn't have spent these billions of dollars on anti-amyloid and anti-tau if they were such obviously terrible ideas.
That's the viewpoint of everyone sensible outside of Alzheimer's research.
Those in it are still throwing billions per year at the idea.
Meanwhile, back in reality, no amyloid-beta drug has had any clinical effect in humans, other than reducing the plaques. But both the shingles and RSV vaccines are proven to reduce Alzheimer's risk.
Which did not stop the FDA from approving a useless anti-amyloid drug, leading to the resignation of several experts, one of whom called it "probably the worst drug approval decision in recent U.S. history" in his resignation letter. [0]
I can't think of a good reason why this happened.
[0] https://www.npr.org/2021/06/11/1005567149/3-experts-have-res...
not really. your comment is a vast oversimplification of a very complicated topic.
if cholesterol predicted future cognitive health we wouldn’t need dedicated tests, do we?
the better way to phrase that would be "is predictive"... there is an association, but it is not high accuracy.
The forecast predicts rain, I'm still going to look outside before I throw on a raincoat
You can do all that without an expensive blood test.
It sounds similar to Lipoprotein(a) blood test for cardiac risk.
It's (almost) purely determined by genetics. You can't do anything to improve it, other than to improve every other cardiac related risk factor.
(There are some experimental drugs in the pipeline, though)
There is an oral PCSK9 treatment (enlicitide) was recently released that provides a 30% reduction, and of course you can't get insurance coverage without the test. And there are 2 drugs with 90%+ reduction in Lp(a) in phase3 trials with expected release in 2027-8, in particular Olpasiran.
I guess you can start spending your retirement money faster
I know it’s a joke but then you’ll leave your family bearing the burden of your care. As someone whose parents had dementia, finding a place that treats your parents with dignity is extremely expensive and very rare. We were spending 12k/month and even we needed to set up camera’s and my sister slept with my mom and took care of her like a nurse. When the pandemic hit my sister couldn’t enter so every morning they took my mom, clothed her and sat her facing the bathroom all day long.
The only other alternative is some sort of mental hospital which is more like a prison than anything else.
Hopefully by the time i’m there euthanasia will be legal
No, a Medicaid funded care facility is the alternative
The sad fact is that some people really should. Many people find it far easier to be or become indigent and fall on Medicaid services. If you do not qualify for Medicaid, then there is a real possibility that your insurance carrier will help put you or your caregivers into massive debt for a long-term illness like this.
If you do go into long-term care, Medicaid will probably seize your assets to help pay for everything. For example, a house in your name. They'll use those to pay back what they paid for your care.
So if you're gonna get sick and you're gonna be a burden in your old age, best to plan for leaving this world the way you came in: naked and penniless.
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.
I am skeptical of 100% anything, so did some looking:
>>Mutations in PSEN1 and APP are associated with complete penetrance, meaning that all individuals who have a PSEN1 or APP mutation will develop AD if they live a normal lifespan [1]
and
>>[Age-of-onset] Usually 40s or early 50s (range 30s-early 60s) [2]
Note that this is only for early-onset Alzheimer's, representing ~5% of all Alzheimer's.
>>Our study showed that the rate of EOAD in AD is 5.5%, not 1-2% as usually demonstrated. And our results indicated that the rate in developed countries was relative higher than in developing countries [3]
[1]https://pmc.ncbi.nlm.nih.gov/articles/PMC3326653/
[2]https://www.ncbi.nlm.nih.gov/books/NBK1161/table/alzheimer.T...
[3]https://pmc.ncbi.nlm.nih.gov/articles/PMC4356853/
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.
I do think telling you to get your affairs in order and to arrange for hospice care is probably good for the doctors. They don't want a family coming in with a sudden decline case and all the information about how to pay for it lost, at minimum
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?
While I’ve nothing to say about these research scientists in particular, knowing precisely nothing about them, it wouldn’t be the first time that so-called ‘bonafide’ research scientists made a statistical boo-boo, even one structural to the research thesis than any sort of math error.
Given the widely-reported extent of p-hacking in the biomedical literature over the decades, I’m surprised anyone would float an avid ‘but how could research scientists ever be wrong’ default reflex.
I can get behind "trust but verify" approach here.
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
thanks!