from Hacker News

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

by wglb on 2/24/26, 3:10 AM with 166 comments

  • by janalsncm on 2/24/26, 3:43 AM

    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 us to figure that out.

  • by aaronrobinson on 2/24/26, 12:36 PM

    We have no cure now but that may change and depend on early detection just as taking meds now can slow the onset. I don’t want to know makes no sense to me. You would plan your whole life differently and it would actually be quite liberating once you’d come to terms with it.

  • by janeway on 2/24/26, 6:39 AM

    “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.

  • by tgv on 2/24/26, 1:21 PM

    A detail, but an important one: the blood test brought the initial diagnosis closer to the final one. The result reflects the agreement between both diagnoses. The usefulness of the blood test depends on the quality of the final diagnosis, which can still be wrong.

  • by TheCapeGreek on 2/24/26, 7:14 AM

    PSA to those with family affected by dementia/Alzheimer's at a relatively early age (say <70yo): Get them tested for STDs, specifically Syphilis.

    Left untreated for a very long time (decade+), it spreads to the brain and causes dementia among other things. Older generations with stigmas, taboos, or from lower educational backgrounds seem (to me) less likely to get tested, so it seems plausible.

    Source: Have recently discovered this myself with a family member from their neurologist.

  • by wglb on 2/24/26, 3:11 AM

  • by shevy-java on 2/24/26, 6:57 AM

    Alarm bells go up. 94.5% in itself is suspicious. It insinuates precision. I highly doubt you can go anywhere near 0.5% correctness.

  • by mariuolo on 2/24/26, 9:12 AM

    Could earlier diagnoses contribute to finding causes and treatments?

  • by bradley13 on 2/24/26, 6:11 AM

    Maybe I've misunderstood something, but how can they know the accuracy of the test? It is the best test out there, so if it misses a diagnosis, how do they reliably catch the false negative?

  • by KurSix on 2/24/26, 10:41 AM

    I'd be curious to see how it performs outside of a specialist neurology setting and in larger, more diverse populations

  • by guerby on 2/24/26, 9:19 AM

    https://pmc.ncbi.nlm.nih.gov/articles/PMC8755961/

    "A narrative review on the effects of a ketogenic diet on patients with Alzheimer's disease"

    https://www.sciencedirect.com/science/article/pii/S127977072...

    "Effects of ketogenic diet on cognitive function of patients with Alzheimer's disease: a systematic review and meta-analysis"

    And anecdotes from the field:

    https://www.youtube.com/watch?v=s86CFw0qhVc

    Revolutionizing Assisted Living: Hal Cranmer's Ketogenic & Carnivore Approach to Senior Wellness / Metabolic Mind

  • by lencastre on 2/24/26, 6:33 AM

    so 94,5% sensitivity, or specificity? this thing with medical testing and false positives is tricky

  • by 8crazyideas on 2/24/26, 7:29 PM

    Sorry, but the test hasn't been shown to be 94.5% accurate. The study was structured as: 1. neurologist makes clinical diagnosis using usual tools and records most likely diagnosis and their confidence in it 2. new p-tau test is done. 3. neurologists reassess their confidence, and change their mind in many cases. There is no "gold standard" here (tough to have in AD) and not even a period of clinical follow-up to assess for any interval change. The study shows that patients got reclassified, but never showed that such reclassification was more accurate than the initial one, and by how much. There is an implication that because in a different, retrospective study the test did show some accuracy, that it would be helpful in this new situation. But that's about it, and different than directly showing this to be the case.

  • by suprgeek on 2/24/26, 4:32 AM

    Since the recent discoveries about Shingles Vaccine delaying dementia https://hsph.harvard.edu/news/link-between-shingles-vaccine-...

    One of interesting checks in this study might be to check when (if) any of the participants had taken this vax and what the impact might be on an Alzimer's diagnosis.

  • by dzink on 2/24/26, 4:17 AM

    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?

  • by toisanji on 2/24/26, 3:40 AM

    Great but the big problem is how to actively treat it. Sleep is a huge factor and that’s a problem for us insomniacs :(

  • by kittikitti on 2/24/26, 10:38 AM

    This is Theranos levels of marketing.

  • by anthk on 2/24/26, 8:50 AM

    40 hz ultrasounds are part of the remedy.

  • by refurb on 2/24/26, 4:30 AM

    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.