4 ms·

We should all get annual blood tests so we can track variance from out baselines.

arcticbull 5y ago
Probably not, honestly. For most tests, the risks associated with a false positive outweigh the benefits of marginally earlier detection. Humans aren't precise machines, each person has different values and different value ranges for standard measurements - and asymptomatic deviations frequently mean nothing whatsoever. On the other hand investigations can be invasive, painful, risky and expensive. There's a reason most tests aren't recommended for folks outside certain risk categories (age, family history, etc). And in a litigious society like America, it's not because it's expensive. There's some specific diseases where there's a lot of data backing this thesis - certain cancers for instance.
- sodality2 5y ago
  > For most tests, the risks associated with a false positive outweigh the benefits of marginally earlier detection. If these tests aren't run, then I am not sure if it would be "marginally earlier", it might be much later or even never that the problem is discovered.
  - plonk 5y ago
    If they are run, the results could be uninformative (https://en.wikipedia.org/wiki/Base_rate_fallacy https://en.wikipedia.org/wiki/Base_rate_fallacy). Too many false positives could lead to risky treatment and be dangerous. Testing each positive again would still create false positives. I don't know the numbers in this case, but I wouldn't be surprised if accurate mass testing were impractically expensive.
    - closedloop129 5y ago
      This should only be a problem if you don't adjust the models. If you run a huge number of tests, you can create far more detailed models and thus reduce the false positive rate. Ideally, all chemical processes in the body could be known and we could have an almost "mechanical" model of the body. How else but with more testing can be reach that knowledge?
      - plonk 5y ago
        > This should only be a problem if you don't adjust the models. If you run a huge number of tests, you can create far more detailed models and thus reduce the false positive rate. Can you? The problem is the test's sensitivity and specificity, there's not much statistical work to do after the test on a single case. It's not an advanced model deciding whether you're sick or not. > Ideally, all chemical processes in the body could be known and we could have an almost "mechanical" model of the body. How else but with more testing can be reach that knowledge? Yeah, ideally we would. Not a doctor, but as far as I can tell, we're a thousand years away from that.
  - wirelesspotat 5y ago
    The video in this comment provides some good examples for why the risks associated with a false positive can be pretty significant: https://news.ycombinator.com/item?id=31126368 https://news.ycombinator.com/item?id=31126368
- tedunangst 5y ago
  That's the whole point of establishing a baseline.
  - deleted 5y ago
    [deleted]
  - solveit 5y ago
    I don't know why this comment is downvoted. Let me elaborate a little on what I think they meant. All the risks associated with false positives (other than the side effects of actually drawing blood once a year, which I think is negligible) can be removed by simply not overreacting. Find a cancer? Well, consider not subjecting yourself to chemo just to get rid of it. Some cancers will kill you by winter, some will just stay there until you die of something else. How will we know which is which? By testing lots of people over long periods of time to see what's harmless and what's actually really bad. Or as the previous commenter said: "That's the whole point of establishing a baseline."
    - arcticbull 5y ago
      The parents premise is wrong. You can't just "establish a better baseline" and "if the test says you might have cancer don't worry about it maybe?" The former is hampered by base rate fallacy [1] (specifically the part about disease in a low-incidence population) and the in the latter, if you're going to disregard the outcome why are you testing? A concrete example is the NHS recommends against the PSA prostate cancer antigen screening test completely for everyone of any age because this test does more harm than good. They have a good write-up on why. [2] Generally I agree this data should be collected, but aggregated and not used for individual treatments. [1] https://en.wikipedia.org/wiki/Base_rate_fallacy https://en.wikipedia.org/wiki/Base_rate_fallacy [2] https://www.nhs.uk/conditions/prostate-cancer/psa-testing/ https://www.nhs.uk/conditions/prostate-cancer/psa-testing/
      - tedunangst 5y ago
        I guess I should have been more clear that by establishing a baseline I did not mean take one test and then have surgery.
- spockz 5y ago
  I think the value in regular blood tests is to get an idea of what normal values are for you specifically. For some diseases/conditions the blood levels have such a big range that it is more useful to know the delta. We hardly ever measure the “good” or stable cases so when we start testing stuff when we are ill there is very little data on what is normal or even normal for you. Ive heard of cars where due to family history someone preemptively screened on certain blood values. When those changed they knew something was up, even though the value was still within normal range it was up 100x for them.
  - arcticbull 5y ago
    Here's a good explanation of why it's not a good idea from Medlife Crisis. [1] h/t wirelesspotat. [1] https://www.youtube.com/watch?v=rW3DGnHO2iY https://www.youtube.com/watch?v=rW3DGnHO2iY
- adrianN 5y ago
  How well do we actually know "normal" values if we don't have the broad data that regular blood tests for everyone could give us?
wirelesspotat 5y ago
There's a great video from Medlife Crisis about why this might not be a good idea "The Problem With Silicon Valley Medicine": https://www.youtube.com/watch?v=rW3DGnHO2iY https://www.youtube.com/watch?v=rW3DGnHO2iY
pkaye 5y ago
Even is the US, a metabolic panel of about 15-20 basic blood tests is only about $40. You an order it online and go to a local lab to get blood drawn.

Probably not, honestly. For most tests, the risks associated with a false positive outweigh the benefits of marginally earlier detection. Humans aren't precise machines, each person has different values and different value ranges for standard measurements - and asymptomatic deviations frequently mean nothing whatsoever. On the other hand investigations can be invasive, painful, risky and expensive. There's a reason most tests aren't recommended for folks outside certain risk categories (age, family history, etc). And in a litigious society like America, it's not because it's expensive. There's some specific diseases where there's a lot of data backing this thesis - certain cancers for instance.

sodality2 5y ago
> For most tests, the risks associated with a false positive outweigh the benefits of marginally earlier detection. If these tests aren't run, then I am not sure if it would be "marginally earlier", it might be much later or even never that the problem is discovered.
- plonk 5y ago
  If they are run, the results could be uninformative (https://en.wikipedia.org/wiki/Base_rate_fallacy https://en.wikipedia.org/wiki/Base_rate_fallacy). Too many false positives could lead to risky treatment and be dangerous. Testing each positive again would still create false positives. I don't know the numbers in this case, but I wouldn't be surprised if accurate mass testing were impractically expensive.
  - closedloop129 5y ago
    This should only be a problem if you don't adjust the models. If you run a huge number of tests, you can create far more detailed models and thus reduce the false positive rate. Ideally, all chemical processes in the body could be known and we could have an almost "mechanical" model of the body. How else but with more testing can be reach that knowledge?
    - plonk 5y ago
      > This should only be a problem if you don't adjust the models. If you run a huge number of tests, you can create far more detailed models and thus reduce the false positive rate. Can you? The problem is the test's sensitivity and specificity, there's not much statistical work to do after the test on a single case. It's not an advanced model deciding whether you're sick or not. > Ideally, all chemical processes in the body could be known and we could have an almost "mechanical" model of the body. How else but with more testing can be reach that knowledge? Yeah, ideally we would. Not a doctor, but as far as I can tell, we're a thousand years away from that.
- wirelesspotat 5y ago
  The video in this comment provides some good examples for why the risks associated with a false positive can be pretty significant: https://news.ycombinator.com/item?id=31126368 https://news.ycombinator.com/item?id=31126368
tedunangst 5y ago
That's the whole point of establishing a baseline.
- deleted 5y ago
  [deleted]
- solveit 5y ago
  I don't know why this comment is downvoted. Let me elaborate a little on what I think they meant. All the risks associated with false positives (other than the side effects of actually drawing blood once a year, which I think is negligible) can be removed by simply not overreacting. Find a cancer? Well, consider not subjecting yourself to chemo just to get rid of it. Some cancers will kill you by winter, some will just stay there until you die of something else. How will we know which is which? By testing lots of people over long periods of time to see what's harmless and what's actually really bad. Or as the previous commenter said: "That's the whole point of establishing a baseline."
  - arcticbull 5y ago
    The parents premise is wrong. You can't just "establish a better baseline" and "if the test says you might have cancer don't worry about it maybe?" The former is hampered by base rate fallacy [1] (specifically the part about disease in a low-incidence population) and the in the latter, if you're going to disregard the outcome why are you testing? A concrete example is the NHS recommends against the PSA prostate cancer antigen screening test completely for everyone of any age because this test does more harm than good. They have a good write-up on why. [2] Generally I agree this data should be collected, but aggregated and not used for individual treatments. [1] https://en.wikipedia.org/wiki/Base_rate_fallacy https://en.wikipedia.org/wiki/Base_rate_fallacy [2] https://www.nhs.uk/conditions/prostate-cancer/psa-testing/ https://www.nhs.uk/conditions/prostate-cancer/psa-testing/
    - tedunangst 5y ago
      I guess I should have been more clear that by establishing a baseline I did not mean take one test and then have surgery.
spockz 5y ago
I think the value in regular blood tests is to get an idea of what normal values are for you specifically. For some diseases/conditions the blood levels have such a big range that it is more useful to know the delta. We hardly ever measure the “good” or stable cases so when we start testing stuff when we are ill there is very little data on what is normal or even normal for you. Ive heard of cars where due to family history someone preemptively screened on certain blood values. When those changed they knew something was up, even though the value was still within normal range it was up 100x for them.
- arcticbull 5y ago
  Here's a good explanation of why it's not a good idea from Medlife Crisis. [1] h/t wirelesspotat. [1] https://www.youtube.com/watch?v=rW3DGnHO2iY https://www.youtube.com/watch?v=rW3DGnHO2iY
adrianN 5y ago
How well do we actually know "normal" values if we don't have the broad data that regular blood tests for everyone could give us?

wirelesspotat 5y ago

There's a great video from Medlife Crisis about why this might not be a good idea "The Problem With Silicon Valley Medicine": https://www.youtube.com/watch?v=rW3DGnHO2iY https://www.youtube.com/watch?v=rW3DGnHO2iY

pkaye 5y ago

Even is the US, a metabolic panel of about 15-20 basic blood tests is only about $40. You an order it online and go to a local lab to get blood drawn.