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Typical usage of blood glucose monitoring (by diabetics) is simultaneously safety critical, and only borderline good enough accuracy. There's a standard metric

Typical usage of blood glucose monitoring (by diabetics) is simultaneously safety critical, and only borderline good enough accuracy. There's a standard metric for accuracy here, MARD (mean absolute relative difference). There is a long history of companies promoting themselves to investors as having working noninvasive glucose monitoring technology, which, if you look at the actual accuracy scores, is only moderately correlated with glucose, nowhere close to the accuracy required. If Apple ships a noninvasive glucose monitor with an MARD of 20, the primary effect will be to set a trap for the stupid: diabetics will attempt to use it to save money, since it will be much cheaper than using real CGMs (which are consumable), and people who try to do this will die.

nosefurhairdo 3y ago
Alternatively, you allow this technology to be sold as a clearly labeled "not accurate enough for treatment of diabetes", and the profit allows more investment in the tech so that one day everyone can benefit from accurate, non-invasive blood glucose monitoring. Or perhaps we should ban everything that can enable "the stupid" to harm themselves.
- Retric 3y ago
  There’s far more options than just those two. It may not be physically possible to have non invasive glucose monitoring of sufficient accuracy, until it’s actually demonstrated we just don’t know. The general point of the FDA is to prevent snake oil salesmen from conning people which makes this decision in line with their core mission.
  - TeMPOraL 3y ago
    > It may not be physically possible to have non invasive glucose monitoring of sufficient accuracy. That's a pretty bold statement. Not economical with current technology? Sure. Not physically possible, at all? I strongly doubt it, and I would love to know the reason for thinking it.
    - bee_rider 3y ago
      The “may” makes it not very bold.
    - veidr 3y ago
      The standard meaning of "non-invasive" with respect to blood glucose monitoring is that you measure blood glucose without the need to puncture/penetrate the skin. We know how to accurately test the blood for various things if we can actually obtain a sample of the blood itself. This is straightforward, but you have to puncture the skin to get the blood. We are starting to be able to infer/guess the blood content of other things, e.g. oxygen, with "useful" accuracy, by measuring externally-detectable changes, such as the color of blood vessels when you shine lights through the skin. But nobody has ever (so far) been able to do this with glucose. It may be possible one day, but we don't know that it is. Even with sensors 1000x or 10000x more precise than we have today, the glucose content of blood still might be just be one of those things that just doesn't manifest enough external changes to be detected non-invasively. Thus, we still might not be able to do it 100 years from now. (I hope we can; I know people with diabetes and I also just want my watch to give me this data about myself because, I mean, why not?)
      - gopher_space 3y ago
        My old dog could sense my mother's low blood glucose from across the room, so I'm assuming we'll all be breathing on our watches before too long.
        kyriakos 3y ago
        But was it sensing low blood sugar itself or the behavioral changes of low blood sugar?
        gopher_space 3y ago
        She'd wake her up in the middle of the night, but there certainly could have been some behavioral cue.
        3y ago
  - wardedVibe 3y ago
    I remember seeing some results from a group using OCT imaging[0] that was on-par with a CGM, just bulky and requiring multiple high-end GPUs to actually run. So it's in principle possible, if nowhere near practical currently [0]: pretty sure it was this https://pubs.acs.org/doi/abs/10.1021/acsnano.1c00497 https://pubs.acs.org/doi/abs/10.1021/acsnano.1c00497
    - Retric 3y ago
      I presume you’re thinking of something else? That approach seems to require injecting nanoparticles and was tested in a simulation of skin not actual skin. Getting bio monitoring tattoo’s is a promising approach, but it’s more involved than just selling a watch.
- Analemma_ 3y ago
  That's the Standard Libertarian Reply, and in some cases it's the one I stand with, but... no, not for this. A label which everybody knows will be ignored (when was the last time you read the EULAs of your software start-to-finish) by people who then inevitably go on to die because their smartwatch gave them a wrong number should not be allowed. > Or perhaps we should ban everything that can enable "the stupid" to harm themselves. Once again this is a case of people holding absolutist principles when there is no need, or benefit, to do so. We can and should use rational cost-benefit analysis to decide what to allow and what to forbid. What's the benefit of allowing non-diabetics access to inaccurate blood sugar measurements? Minimal: a couple people have mentioned speculative uses about mood or energy level, but that's about it. What's the harm? Colossal: it's a near-certainty that many people will die. This is a no-brainer. Note that by contrast, the calculus for allowing somewhat-inaccurate EKG measurements on the Apple Watch is in favor of allowing it: nobody is going to live or die on an inaccurate heartbeat trace from their watch, as they can for a blood glucose measurement, so, sure, why not. Again: black-and-white principles is not the correct mode of analysis here.
- veidr 3y ago
  Well, you are describing the maximally absurd end of that spectrum to make your point, but in the US the FDA does indeed ban all kinds of stuff to prevent both its sale, and use (i.e. to stop "the stupid" from using it). Blood glucose monitors are sold without a prescription in many countries, and you can buy them with varying degrees of accuracy and use them for whatever you want; not in the US, though, because they are regulated as medical devices. The same is true for lots of other stuff that could be used in non-medical or less-dangerous medical contexts, like nebulizers. You can make a reasonable argument for your position, regarding this specific device or more generally. But the FDA has consistently rejected it.
  - jprival 3y ago
    Worth noting that glucose meters are OTC. Continuous monitoring solutions generally seem to require a prescription, though there are telehealth companies that will help you sort that out. According to the article what the FDA really objects to is “non-invasive” glucose monitoring devices of any sort, on the grounds of general lack of evidence of accuracy.
    - veidr 3y ago
      Yeah, noteworthy point. Also, I think the article is weirdly sensationalized — the FDA isn't "against" anything here. If you click through to the FDA's bulletin[1], it's merely stating for clarity and public awareness that there are currently no non-invasive CGM devices that actually meet existing standards for accuracy. If somebody did produce one, it could be validated and approved via the same processes used by all the existing CGM products which have been approved. [1]: https://www.fda.gov/medical-devices/safety-communications/do-not-use-smartwatches-or-smart-rings-measure-blood-glucose-levels-fda-safety-communication https://www.fda.gov/medical-devices/safety-communications/do...
- smitty1e 3y ago
  > Or perhaps we should ban everything that can enable "the stupid" to harm themselves. Quite a bit of capitalism is predicated on the market not being very bright.

nosefurhairdo 3y ago

Alternatively, you allow this technology to be sold as a clearly labeled "not accurate enough for treatment of diabetes", and the profit allows more investment in the tech so that one day everyone can benefit from accurate, non-invasive blood glucose monitoring. Or perhaps we should ban everything that can enable "the stupid" to harm themselves.

Retric 3y ago
There’s far more options than just those two. It may not be physically possible to have non invasive glucose monitoring of sufficient accuracy, until it’s actually demonstrated we just don’t know. The general point of the FDA is to prevent snake oil salesmen from conning people which makes this decision in line with their core mission.
- TeMPOraL 3y ago
  > It may not be physically possible to have non invasive glucose monitoring of sufficient accuracy. That's a pretty bold statement. Not economical with current technology? Sure. Not physically possible, at all? I strongly doubt it, and I would love to know the reason for thinking it.
  - bee_rider 3y ago
    The “may” makes it not very bold.
  - veidr 3y ago
    The standard meaning of "non-invasive" with respect to blood glucose monitoring is that you measure blood glucose without the need to puncture/penetrate the skin. We know how to accurately test the blood for various things if we can actually obtain a sample of the blood itself. This is straightforward, but you have to puncture the skin to get the blood. We are starting to be able to infer/guess the blood content of other things, e.g. oxygen, with "useful" accuracy, by measuring externally-detectable changes, such as the color of blood vessels when you shine lights through the skin. But nobody has ever (so far) been able to do this with glucose. It may be possible one day, but we don't know that it is. Even with sensors 1000x or 10000x more precise than we have today, the glucose content of blood still might be just be one of those things that just doesn't manifest enough external changes to be detected non-invasively. Thus, we still might not be able to do it 100 years from now. (I hope we can; I know people with diabetes and I also just want my watch to give me this data about myself because, I mean, why not?)
    - gopher_space 3y ago
      My old dog could sense my mother's low blood glucose from across the room, so I'm assuming we'll all be breathing on our watches before too long.
      - kyriakos 3y ago
        But was it sensing low blood sugar itself or the behavioral changes of low blood sugar?
        gopher_space 3y ago
        She'd wake her up in the middle of the night, but there certainly could have been some behavioral cue.
        3y ago
- wardedVibe 3y ago
  I remember seeing some results from a group using OCT imaging[0] that was on-par with a CGM, just bulky and requiring multiple high-end GPUs to actually run. So it's in principle possible, if nowhere near practical currently [0]: pretty sure it was this https://pubs.acs.org/doi/abs/10.1021/acsnano.1c00497 https://pubs.acs.org/doi/abs/10.1021/acsnano.1c00497
  - Retric 3y ago
    I presume you’re thinking of something else? That approach seems to require injecting nanoparticles and was tested in a simulation of skin not actual skin. Getting bio monitoring tattoo’s is a promising approach, but it’s more involved than just selling a watch.
Analemma_ 3y ago
That's the Standard Libertarian Reply, and in some cases it's the one I stand with, but... no, not for this. A label which everybody knows will be ignored (when was the last time you read the EULAs of your software start-to-finish) by people who then inevitably go on to die because their smartwatch gave them a wrong number should not be allowed. > Or perhaps we should ban everything that can enable "the stupid" to harm themselves. Once again this is a case of people holding absolutist principles when there is no need, or benefit, to do so. We can and should use rational cost-benefit analysis to decide what to allow and what to forbid. What's the benefit of allowing non-diabetics access to inaccurate blood sugar measurements? Minimal: a couple people have mentioned speculative uses about mood or energy level, but that's about it. What's the harm? Colossal: it's a near-certainty that many people will die. This is a no-brainer. Note that by contrast, the calculus for allowing somewhat-inaccurate EKG measurements on the Apple Watch is in favor of allowing it: nobody is going to live or die on an inaccurate heartbeat trace from their watch, as they can for a blood glucose measurement, so, sure, why not. Again: black-and-white principles is not the correct mode of analysis here.
veidr 3y ago
Well, you are describing the maximally absurd end of that spectrum to make your point, but in the US the FDA does indeed ban all kinds of stuff to prevent both its sale, and use (i.e. to stop "the stupid" from using it). Blood glucose monitors are sold without a prescription in many countries, and you can buy them with varying degrees of accuracy and use them for whatever you want; not in the US, though, because they are regulated as medical devices. The same is true for lots of other stuff that could be used in non-medical or less-dangerous medical contexts, like nebulizers. You can make a reasonable argument for your position, regarding this specific device or more generally. But the FDA has consistently rejected it.
- jprival 3y ago
  Worth noting that glucose meters are OTC. Continuous monitoring solutions generally seem to require a prescription, though there are telehealth companies that will help you sort that out. According to the article what the FDA really objects to is “non-invasive” glucose monitoring devices of any sort, on the grounds of general lack of evidence of accuracy.
  - veidr 3y ago
    Yeah, noteworthy point. Also, I think the article is weirdly sensationalized — the FDA isn't "against" anything here. If you click through to the FDA's bulletin[1], it's merely stating for clarity and public awareness that there are currently no non-invasive CGM devices that actually meet existing standards for accuracy. If somebody did produce one, it could be validated and approved via the same processes used by all the existing CGM products which have been approved. [1]: https://www.fda.gov/medical-devices/safety-communications/do-not-use-smartwatches-or-smart-rings-measure-blood-glucose-levels-fda-safety-communication https://www.fda.gov/medical-devices/safety-communications/do...
smitty1e 3y ago
> Or perhaps we should ban everything that can enable "the stupid" to harm themselves. Quite a bit of capitalism is predicated on the market not being very bright.