9 ms·

I dove into CGMs a little bit about a year ago, mostly just for fun. Yes, I paid money to some online prescription mill for CGMs (Abbott Freestyle Libre 3, IIR

I dove into CGMs a little bit about a year ago, mostly just for fun. Yes, I paid money to some online prescription mill for CGMs (Abbott Freestyle Libre 3, IIRC), and then put one in my arm (the applicator is a short syringe section that has the monitor tube threaded into it, so the tube stays in your arm and your skin under the monitor remains broken) for a couple weeks. Just to see how various foods would affect my blood glucose, to see whether the “facts” I’m telling my kids about the glycemic index of various foods actually has the expected impact on a measurable result. You know, as you do. For fun. (It actually was fun, and I’ll do it again when the data ecosystem improves.)

hasty_pudding 3y ago
I would love to see the results of that!
haswell 3y ago
Aside from the fun, how did it go? Find anything surprising or insightful in the process? It sounds like an experiment I’d like to do for the purpose of optimizing my daily habits and establishing a better mental model for how my eating habits impact me throughout the day. But I really dislike needles.
- smt88 3y ago
  If the needle in the CGM bothers you, don't let it. It's a quick, painless jab with a tiny needle at the beginning and then the needle comes out. The part that stays in your body is just a flexible filament made of plastic. I did this experiment as well, and the main thing it did was completely stop me from snacking. My habits got better because I could see how my BG could never return to baseline if I allowed myself to snack between meals. Other than that, it was also interesting to see certain things would badly spike my BG and other things wouldn't, and they weren't always what you'd expect. A lot of "keto" and "diabetic-friendly" products are terrible for most people's BG and were for mine. I found that some things, like black tea, actually made my BG drop as well. Overall it's worth doing at least once.
  - coffeebeqn 3y ago
    Where do you put the needle thing? Does it get in the way of everyday things?
    - singlow 3y ago
      Typically it is on the back of the upper arm where it is covered by a short sleeve shirt. Generally it does not get in the way.
      - RecycledEle 3y ago
        I also use a piece of kinesiology tape to make sure my CGM does not fall off.
    - Aqua_Geek 3y ago
      The sensor typically goes on the back of your upper arm (your tricep). You can accidentally bump into things with it, but it was infrequent enough that it didn’t bother me. The needle is only used in the application of the sensor. It’s spring-loaded and retracts after the sensor is attached. I hate needles, but I found that the tape on the sensor provided enough stimuli to overwhelm my brain and not really feel the needle when it went in.
    - pastage 3y ago
      No it never gets in the way. I would not recommend doing it unless you are a diabetic, the results are not that interesting. It took me two years to get used to smacking that needle into the upper arm/stomach/leg, spending up to 20 min -40 min getting over the fear was not a fun time.
      - RecycledEle 3y ago
        I feel for anyone who has both diabetes and a fear of needles. Having said that, it's no bug deal for 90% of people.
        3y ago
- pastage 3y ago
  If you want to know more about it you can just read about how diabetics treat different foods. Short version; high GI is fast high blood sugar, lots fat and sugar can results long period of with high blood sugars. It is a CGM more or less what you would expect, insulin is the only hormone that lowers blood sugar, then you have all the stress hormones that raise it like adrenalin, growth hormone and cortisol plus glucagon for long time storage of sugars in the body. So measuring blood sugar with a CGM gives you a value between 2.9-13.5 mmol/liter that is supposed to give you picture of a rather complex system. A CGM also needs perfect access to your free flowing blood which in it self is a difficult task.
  - haswell 3y ago
    I'm more curious about the experience a non-diabetic person has. For one, the purpose of using the device is quite different, and not related to a life threatening situation. And because the focus isn't to manage this specific issue, the insights and potential utility seem like they'd be of an entirely different variety. e.g. I know that the things I eat impact my blood sugar, but don't have the same kind of intimate awareness a diabetic person would have, nor would the changes in my levels have the same meaning/impact. Put another way, and setting aside the issue of oversimplifying a complex system (so is measuring RHR, HRV, blood oxygen, etc.), the benefit of CGM for a diabetic person is obvious. The benefit of CGM for a curious person less so.
    - Projectiboga 3y ago
      Main benefit is more data, only work is to accurately log meals and activity.
    - pastage 3y ago
      It is probably easier to find interesting things curious people with diabetes has done, sure you might want help to sort out the interesting bits. Optimizing sugar in take for exercise might be an interesting thing todo as non diabetic. There is no tool to continuously measure ketons though which is the fun part. CGMs are so slow. I really see no use at the moment.
  - 3y ago
- galago 3y ago
  Freestyle Libre 3 only has a plastic filament and the plastic applicator pushes it in without pain. Very different than metal lancets (stick test). I can't feel it at all when its in the back of my arm. If I were worried about sweating too much and it not sticking I would get one of the third party over-patches that create a lager adhesive area. I might do that in the Summer.
  - spc476 3y ago
    My girlfriend uses the Libre 3 and I was wondering how it worked with just that plastic filament. She doesn't feel it at all when I apply it. We found that if she washes the area with soap and then just relaxes her arm and lets it hang freely, I apply it to the back upper arm, it just stays on and doesn't get in the way.
- crimsontech 3y ago
  I did it for fun about a year ago and found out I had T2 diabetes. I was shocked but obviously glad I found out. I use them from time to time just to see how I’m doing and how different foods (and amounts of them) impact me. I found I can control it through diet alone and exercising when there is a spike by using a GCM for the constant feedback. They are very expensive here though (UK) and my doctor won’t prescribe me one because metformin is cheaper, so it’s not something I can use all the time. I hate needles, this really isn’t like a needle though, it’s a small filament which sits just under your skin, you can’t feel it, I thought it hadn’t gone in until I saw the reading appear on my phone. Some things I found out besides what foods and amounts give me big spikes are that I have a blood glucose spike in the morning just before I wake up, and that if I eat a small enough portion of white rice, ice cream, bread, whatever I can reduce the spike quickly by going for a walk. If I had a lot though, a walk isn’t going to help.
- philsnow 3y ago
  I almost completely forgot about the monitor itself, and only paid attention to the numbers on my phone. It's that unobtrusive (at least the Libre 3 one that I used). I let the needle (actually: annulus? see sibling comment) get into my head because I was curious and looked at it. It looks a lot scarier than it is, kind of like using contact lenses for the first time: before you've used them, you get into your own head about it, but once you've done it a couple times it's just rote and easy. I had started the first one a day before I started a few weeks of (6-days-on, 1-day-off) keto. Keto guides will say that you should have <= 25g net carbs per day, but I specifically wanted to see how front-loading (having almost all the day's planned carbs in one meal) affected blood glucose, and also whether the number (25g) is accurate for my physiology. I found that my number was closer to 30g and that when I stayed under it, my blood glucose spikes had very short duration but when I went significantly over it, blood glucose stayed higher for longer. edit: One more thing, I used this time to play around with various sugar substitutes and see how they affected my blood glucose. Allulose came out as the winner (if money is no object) based on not having any noticeable off-taste or aftertaste and on measuring gram-for-gram the same as sugar (well sort of, it's only like 80% as sweet as sugar, so you get the same mechanical effects of sugar if you weigh it gram-for-gram and your baked goods or whatever come out not quite as sweet, which is perfect for me. Creaming butter with liquid stevia extract or something just plain doesn't work.
  - deleted 3y ago
    [deleted]
  - LegitShady 3y ago
    what other sweeteners did you try? Can't get allulose in canada (unless you buy it from a shady importer) because Health Canada says there isn't enough data to say its safe, so its not approved sweetener.
itpragmatik 3y ago
At least for me the readings that it shows are not accurate (when verified with old style finger pricking glucose monitoring machine). These CGMs are good for knowing the general variability of glucose level in your blood based on your diet exercise etc; I don’t trust the absolute numbers from CGM like Freestyle Libre - haven’t used any other one though yet.
- reaperman 3y ago
  It would be interesting to see whether a group of 20-100 people could manually calibrate their readings by fitting their CGM readings to their fingerprick glucose readers. I wonder what the accuracy would be after a very basic personal curve fit. I do this with a lot of consumer measurement devices. Both for thermometers and scales (food, human, and cheap 0.1mg scales). As well as thermostats, like the kitchen oven. I also do it for my multimeters. I validate my volumetric measuring cups/spoons by weighing water in them but I don’t correct them, just return if they’re way off. It’s okay if the reading is off as long as I can correct it the same way every time and get a pretty accurate result.
  - alright2565 3y ago
    Calibrating my scales and thermometers would be nice. What procedure do you use for it? is it documented online anywhere?
    - reaperman 3y ago
      I basically use an Excel sheet. Make a scatter plot of the "true" values on one axis, and the "measured (slightly wrong)" values on another axis. Then do best-fit to y=mx+b and manually adjust it according to that equation using my phone calculator in the future. Some classically trained engineers may tell you the "true" value should always be plotted on the x-axis as it is often considered to be the more "independent" variable...but this is highly debatable, and you can skip some simple algebra later if you put the measured value on the x-axis. Then look at the shape of the scatter plot. Ideally it will be linear, so you ask Excel to do a linear curve fit (y=m*x+b). Write this on the scale, and now whenever you take a measurement on the scale, whip out your phone and do "measured_value * m + b". And that's your true value. If it's not a linear fit (quadratic, log, etc) ... that's interesting, and often it's likely "wrong", but also "it is what it is". Classically trained engineers will say you have to do a linear fit if that's what the theory says is appropriate, but for one-off home device calibration...do whatever works for you. Just as long as you don't overfit with some stupid 4, 5, 6, etc-term equation. Any reasonably simple equation with 2-3 terms is fine IMHO. I use a set of heavy objects whose mass I know fairly precisely. They're not perfectly 10.000lbs, 20.000lbs, etc ... they're just "around 10lbs, around 20lbs" and I've used a good actually-calibrated scale (at work, some commercial business with calibrated scales that you can access, whatever) to weigh them and wrote their weights in sharpie on a piece of tape stuck to the objects. Ideally you'd go for around 10% increments. If the scale can weigh 400lbs, that would be every 40 lbs or so. But it really doesn't matter as long as you have enough good points around the range you truly intend to measure, and then a few outside of that target range at semi-regular intervals. For my 0.1mg-resolution mass balance I have some actual calibration weights, but they're a relatively affordable OIML "M1" class, and did not come with expensive calibration certificates. The OIML tolerance ratings go E1, E2, F1, F2, M1, M2, M3 (from best to worst). For a 100g test weight, M1 precision gets you +/- 0.005g, guaranteed, for $50 ($135 if you want a calibration certificate). E1 gets you +/- 0.00005g at 100g test weight, for $500 ($1200 with cal cert). For smaller calibration weights like 10mg you'll generally want to go a step up from M1 (+/- 0.25mg) to F2 (+/- 0.08mg) for about $27. For temperature, it's a bit trickier because the only "true" temperatures you can create are -6°F/-21°C and 228°F/109°C. If these temperatures are helpful to you, you can create them by pouring shitloads of salt in water and stirring+heating it until no more salt will dissolve and you just have a pile of salt in the bottom of the container. You can try to go for "0°C/100°C" using distilled water and it would probably be close enough but you can't know it exactly unless you use super pure de-ionized water and use extremely absurd lab technique (usually involving washing your glassware and tools with de-ionized water over and over for several days straight to get rid of trace contaminants). So instead, to get "true" temperature in the range I care about, I use some thermocouples attached to a high-quality multimeter or oscilloscope. Then I calibrate these thermocouples using the method above, and average their reading for the oven temperature. This works and extrapolates well enough outside the range of calibration because the error of a thermocouple is basically guaranteed to be a very linear error. In this link[0] topics 1-6 ("weeks") get into the fine details of all this and provide some worksheets/excel sheets already made up for this type of thing. If you're really getting into the weeds with this, understanding propagation of error[1] really helps but is super unnecessary for 99% of people unless they're doing actual engineering. 0: https://pages.mtu.edu/~fmorriso/cm3215/laboratory_exercise_schedule.html https://pages.mtu.edu/~fmorriso/cm3215/laboratory_exercise_s... 1: https://pages.mtu.edu/~fmorriso/Pintar_Error_Analysis_or_UO_Lab.pdf https://pages.mtu.edu/~fmorriso/Pintar_Error_Analysis_or_UO_...
deleted 3y ago
[deleted]
turtlebits 3y ago
Same, but my doctor pointed me to a promotion for a free sensor. It did require a prescription, but since I don't have diabetes, it's not covered by insurance. Trying to get it filled and picked up was slightly annoying as the pharmacy initially did not want to fill it without some prodding, and I waited a while for them to figure out how to get the promotion billed.
znpy 3y ago
What's the lifetime of a single device? Are you supposed to remove it before a shower and reapply it later?
- hlfshell 3y ago
  No, it's mostly water proof. You wear it through showers and even swimming for 2 straight weeks. The adhesive is pretty good; rarely does it come off on its own prior to say, a week and a half in. It holds 8 hours of data (1 reading per minute) and you can just hold up your phone to read the last 8 hours of data for your overall data.
  - znpy 3y ago
    thanks for the reply!
deleted 3y ago
[deleted]
jseliger 3y ago
Before I got cancer, I had one through Levels, and it was informative. Dessert is much worse than I'd thought. Rice, too, including brown rice. I remember eating some biryani and a small bit of naan at an Indian restaurant and thinking that I'd been pretty healthy, only to see a spike of like 80.
- meindnoch 3y ago
  Momentary high blood sugar is perfectly fine after eating carbohydrate-rich meals.
  - Retric 3y ago
    This was down voted, but it's all about the time scale. A major pathway of transporting energy from your food to your cells is via glucose in your blood and your cells then use or store it for later. Insulin production reduces the spike, but that response isn't instantaneous. So on a second by second basis numbers that would be concerning across an hour are fine. Similarly your average over an hour post meal can be much higher than a healthy average across a day.
    - TylerE 3y ago
      Yup. A1C, which is the main diagnostic measure, due to the way it’s measured is a roughly 90 day moving average with somewhat of a recency bias. Like most things, it’s mostly about area under the curve, as long as the extremes aren’t too much so.
  - EasyMark 3y ago
    for sure, the length of the spike is just as important, it's like energy and it's an area under the curve type of phenomena
- colordrops 3y ago
  Is 80 high? That seems totally fine.
  - 3y ago
gregschlom 3y ago
> so the tube stays in your arm and your skin under the monitor remains broken That's not how it works, at least for the Freestyle Libre 3. The cross section of the needle has C shape rather than a O (technically I believe it's called a cannula). When you remove the applicator that C shape allows the needle to be removed through the hole at the top of the sensor, and only the flexible filament stays I your arm.
- rnewme 3y ago
  I belive he called the flexible filament "tube" and that you are both saying the same thing. Ie skin stays open (albeit in very tiny spot where the filament is sticked in)
barbazoo 3y ago
What symptoms would one have to present for an "online prescription mill"/"virtual care provider" to prescribe a CGM? I'm fascinated by this and would love to try it out but I don't want to bother my family doctor with this.
- CaptainNegative 3y ago
  The only symptoms needed are a pulse, the ability to type out a credit card number, and availability for a sham phone call. It's virtually impossible to not get prescribed one from a mill.
  - EasyMark 3y ago
    How much would a month or two cost me if it was out of pocket? I wouldn't mind doing it for science.

hasty_pudding 3y ago

I would love to see the results of that!

haswell 3y ago

Aside from the fun, how did it go? Find anything surprising or insightful in the process? It sounds like an experiment I’d like to do for the purpose of optimizing my daily habits and establishing a better mental model for how my eating habits impact me throughout the day. But I really dislike needles.

smt88 3y ago
If the needle in the CGM bothers you, don't let it. It's a quick, painless jab with a tiny needle at the beginning and then the needle comes out. The part that stays in your body is just a flexible filament made of plastic. I did this experiment as well, and the main thing it did was completely stop me from snacking. My habits got better because I could see how my BG could never return to baseline if I allowed myself to snack between meals. Other than that, it was also interesting to see certain things would badly spike my BG and other things wouldn't, and they weren't always what you'd expect. A lot of "keto" and "diabetic-friendly" products are terrible for most people's BG and were for mine. I found that some things, like black tea, actually made my BG drop as well. Overall it's worth doing at least once.
- coffeebeqn 3y ago
  Where do you put the needle thing? Does it get in the way of everyday things?
  - singlow 3y ago
    Typically it is on the back of the upper arm where it is covered by a short sleeve shirt. Generally it does not get in the way.
    - RecycledEle 3y ago
      I also use a piece of kinesiology tape to make sure my CGM does not fall off.
  - Aqua_Geek 3y ago
    The sensor typically goes on the back of your upper arm (your tricep). You can accidentally bump into things with it, but it was infrequent enough that it didn’t bother me. The needle is only used in the application of the sensor. It’s spring-loaded and retracts after the sensor is attached. I hate needles, but I found that the tape on the sensor provided enough stimuli to overwhelm my brain and not really feel the needle when it went in.
  - pastage 3y ago
    No it never gets in the way. I would not recommend doing it unless you are a diabetic, the results are not that interesting. It took me two years to get used to smacking that needle into the upper arm/stomach/leg, spending up to 20 min -40 min getting over the fear was not a fun time.
    - RecycledEle 3y ago
      I feel for anyone who has both diabetes and a fear of needles. Having said that, it's no bug deal for 90% of people.
      - 3y ago
pastage 3y ago
If you want to know more about it you can just read about how diabetics treat different foods. Short version; high GI is fast high blood sugar, lots fat and sugar can results long period of with high blood sugars. It is a CGM more or less what you would expect, insulin is the only hormone that lowers blood sugar, then you have all the stress hormones that raise it like adrenalin, growth hormone and cortisol plus glucagon for long time storage of sugars in the body. So measuring blood sugar with a CGM gives you a value between 2.9-13.5 mmol/liter that is supposed to give you picture of a rather complex system. A CGM also needs perfect access to your free flowing blood which in it self is a difficult task.
- haswell 3y ago
  I'm more curious about the experience a non-diabetic person has. For one, the purpose of using the device is quite different, and not related to a life threatening situation. And because the focus isn't to manage this specific issue, the insights and potential utility seem like they'd be of an entirely different variety. e.g. I know that the things I eat impact my blood sugar, but don't have the same kind of intimate awareness a diabetic person would have, nor would the changes in my levels have the same meaning/impact. Put another way, and setting aside the issue of oversimplifying a complex system (so is measuring RHR, HRV, blood oxygen, etc.), the benefit of CGM for a diabetic person is obvious. The benefit of CGM for a curious person less so.
  - Projectiboga 3y ago
    Main benefit is more data, only work is to accurately log meals and activity.
  - pastage 3y ago
    It is probably easier to find interesting things curious people with diabetes has done, sure you might want help to sort out the interesting bits. Optimizing sugar in take for exercise might be an interesting thing todo as non diabetic. There is no tool to continuously measure ketons though which is the fun part. CGMs are so slow. I really see no use at the moment.
- 3y ago
galago 3y ago
Freestyle Libre 3 only has a plastic filament and the plastic applicator pushes it in without pain. Very different than metal lancets (stick test). I can't feel it at all when its in the back of my arm. If I were worried about sweating too much and it not sticking I would get one of the third party over-patches that create a lager adhesive area. I might do that in the Summer.
- spc476 3y ago
  My girlfriend uses the Libre 3 and I was wondering how it worked with just that plastic filament. She doesn't feel it at all when I apply it. We found that if she washes the area with soap and then just relaxes her arm and lets it hang freely, I apply it to the back upper arm, it just stays on and doesn't get in the way.
crimsontech 3y ago
I did it for fun about a year ago and found out I had T2 diabetes. I was shocked but obviously glad I found out. I use them from time to time just to see how I’m doing and how different foods (and amounts of them) impact me. I found I can control it through diet alone and exercising when there is a spike by using a GCM for the constant feedback. They are very expensive here though (UK) and my doctor won’t prescribe me one because metformin is cheaper, so it’s not something I can use all the time. I hate needles, this really isn’t like a needle though, it’s a small filament which sits just under your skin, you can’t feel it, I thought it hadn’t gone in until I saw the reading appear on my phone. Some things I found out besides what foods and amounts give me big spikes are that I have a blood glucose spike in the morning just before I wake up, and that if I eat a small enough portion of white rice, ice cream, bread, whatever I can reduce the spike quickly by going for a walk. If I had a lot though, a walk isn’t going to help.
philsnow 3y ago
I almost completely forgot about the monitor itself, and only paid attention to the numbers on my phone. It's that unobtrusive (at least the Libre 3 one that I used). I let the needle (actually: annulus? see sibling comment) get into my head because I was curious and looked at it. It looks a lot scarier than it is, kind of like using contact lenses for the first time: before you've used them, you get into your own head about it, but once you've done it a couple times it's just rote and easy. I had started the first one a day before I started a few weeks of (6-days-on, 1-day-off) keto. Keto guides will say that you should have <= 25g net carbs per day, but I specifically wanted to see how front-loading (having almost all the day's planned carbs in one meal) affected blood glucose, and also whether the number (25g) is accurate for my physiology. I found that my number was closer to 30g and that when I stayed under it, my blood glucose spikes had very short duration but when I went significantly over it, blood glucose stayed higher for longer. edit: One more thing, I used this time to play around with various sugar substitutes and see how they affected my blood glucose. Allulose came out as the winner (if money is no object) based on not having any noticeable off-taste or aftertaste and on measuring gram-for-gram the same as sugar (well sort of, it's only like 80% as sweet as sugar, so you get the same mechanical effects of sugar if you weigh it gram-for-gram and your baked goods or whatever come out not quite as sweet, which is perfect for me. Creaming butter with liquid stevia extract or something just plain doesn't work.
- deleted 3y ago
  [deleted]
- LegitShady 3y ago
  what other sweeteners did you try? Can't get allulose in canada (unless you buy it from a shady importer) because Health Canada says there isn't enough data to say its safe, so its not approved sweetener.

itpragmatik 3y ago

At least for me the readings that it shows are not accurate (when verified with old style finger pricking glucose monitoring machine). These CGMs are good for knowing the general variability of glucose level in your blood based on your diet exercise etc; I don’t trust the absolute numbers from CGM like Freestyle Libre - haven’t used any other one though yet.

reaperman 3y ago
It would be interesting to see whether a group of 20-100 people could manually calibrate their readings by fitting their CGM readings to their fingerprick glucose readers. I wonder what the accuracy would be after a very basic personal curve fit. I do this with a lot of consumer measurement devices. Both for thermometers and scales (food, human, and cheap 0.1mg scales). As well as thermostats, like the kitchen oven. I also do it for my multimeters. I validate my volumetric measuring cups/spoons by weighing water in them but I don’t correct them, just return if they’re way off. It’s okay if the reading is off as long as I can correct it the same way every time and get a pretty accurate result.
- alright2565 3y ago
  Calibrating my scales and thermometers would be nice. What procedure do you use for it? is it documented online anywhere?
  - reaperman 3y ago
    I basically use an Excel sheet. Make a scatter plot of the "true" values on one axis, and the "measured (slightly wrong)" values on another axis. Then do best-fit to y=mx+b and manually adjust it according to that equation using my phone calculator in the future. Some classically trained engineers may tell you the "true" value should always be plotted on the x-axis as it is often considered to be the more "independent" variable...but this is highly debatable, and you can skip some simple algebra later if you put the measured value on the x-axis. Then look at the shape of the scatter plot. Ideally it will be linear, so you ask Excel to do a linear curve fit (y=m*x+b). Write this on the scale, and now whenever you take a measurement on the scale, whip out your phone and do "measured_value * m + b". And that's your true value. If it's not a linear fit (quadratic, log, etc) ... that's interesting, and often it's likely "wrong", but also "it is what it is". Classically trained engineers will say you have to do a linear fit if that's what the theory says is appropriate, but for one-off home device calibration...do whatever works for you. Just as long as you don't overfit with some stupid 4, 5, 6, etc-term equation. Any reasonably simple equation with 2-3 terms is fine IMHO. I use a set of heavy objects whose mass I know fairly precisely. They're not perfectly 10.000lbs, 20.000lbs, etc ... they're just "around 10lbs, around 20lbs" and I've used a good actually-calibrated scale (at work, some commercial business with calibrated scales that you can access, whatever) to weigh them and wrote their weights in sharpie on a piece of tape stuck to the objects. Ideally you'd go for around 10% increments. If the scale can weigh 400lbs, that would be every 40 lbs or so. But it really doesn't matter as long as you have enough good points around the range you truly intend to measure, and then a few outside of that target range at semi-regular intervals. For my 0.1mg-resolution mass balance I have some actual calibration weights, but they're a relatively affordable OIML "M1" class, and did not come with expensive calibration certificates. The OIML tolerance ratings go E1, E2, F1, F2, M1, M2, M3 (from best to worst). For a 100g test weight, M1 precision gets you +/- 0.005g, guaranteed, for $50 ($135 if you want a calibration certificate). E1 gets you +/- 0.00005g at 100g test weight, for $500 ($1200 with cal cert). For smaller calibration weights like 10mg you'll generally want to go a step up from M1 (+/- 0.25mg) to F2 (+/- 0.08mg) for about $27. For temperature, it's a bit trickier because the only "true" temperatures you can create are -6°F/-21°C and 228°F/109°C. If these temperatures are helpful to you, you can create them by pouring shitloads of salt in water and stirring+heating it until no more salt will dissolve and you just have a pile of salt in the bottom of the container. You can try to go for "0°C/100°C" using distilled water and it would probably be close enough but you can't know it exactly unless you use super pure de-ionized water and use extremely absurd lab technique (usually involving washing your glassware and tools with de-ionized water over and over for several days straight to get rid of trace contaminants). So instead, to get "true" temperature in the range I care about, I use some thermocouples attached to a high-quality multimeter or oscilloscope. Then I calibrate these thermocouples using the method above, and average their reading for the oven temperature. This works and extrapolates well enough outside the range of calibration because the error of a thermocouple is basically guaranteed to be a very linear error. In this link[0] topics 1-6 ("weeks") get into the fine details of all this and provide some worksheets/excel sheets already made up for this type of thing. If you're really getting into the weeds with this, understanding propagation of error[1] really helps but is super unnecessary for 99% of people unless they're doing actual engineering. 0: https://pages.mtu.edu/~fmorriso/cm3215/laboratory_exercise_schedule.html https://pages.mtu.edu/~fmorriso/cm3215/laboratory_exercise_s... 1: https://pages.mtu.edu/~fmorriso/Pintar_Error_Analysis_or_UO_Lab.pdf https://pages.mtu.edu/~fmorriso/Pintar_Error_Analysis_or_UO_...

deleted 3y ago

[deleted]

turtlebits 3y ago

Same, but my doctor pointed me to a promotion for a free sensor. It did require a prescription, but since I don't have diabetes, it's not covered by insurance. Trying to get it filled and picked up was slightly annoying as the pharmacy initially did not want to fill it without some prodding, and I waited a while for them to figure out how to get the promotion billed.

znpy 3y ago

What's the lifetime of a single device? Are you supposed to remove it before a shower and reapply it later?

hlfshell 3y ago
No, it's mostly water proof. You wear it through showers and even swimming for 2 straight weeks. The adhesive is pretty good; rarely does it come off on its own prior to say, a week and a half in. It holds 8 hours of data (1 reading per minute) and you can just hold up your phone to read the last 8 hours of data for your overall data.
- znpy 3y ago
  thanks for the reply!

deleted 3y ago

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jseliger 3y ago

Before I got cancer, I had one through Levels, and it was informative. Dessert is much worse than I'd thought. Rice, too, including brown rice. I remember eating some biryani and a small bit of naan at an Indian restaurant and thinking that I'd been pretty healthy, only to see a spike of like 80.

meindnoch 3y ago
Momentary high blood sugar is perfectly fine after eating carbohydrate-rich meals.
- Retric 3y ago
  This was down voted, but it's all about the time scale. A major pathway of transporting energy from your food to your cells is via glucose in your blood and your cells then use or store it for later. Insulin production reduces the spike, but that response isn't instantaneous. So on a second by second basis numbers that would be concerning across an hour are fine. Similarly your average over an hour post meal can be much higher than a healthy average across a day.
  - TylerE 3y ago
    Yup. A1C, which is the main diagnostic measure, due to the way it’s measured is a roughly 90 day moving average with somewhat of a recency bias. Like most things, it’s mostly about area under the curve, as long as the extremes aren’t too much so.
- EasyMark 3y ago
  for sure, the length of the spike is just as important, it's like energy and it's an area under the curve type of phenomena
colordrops 3y ago
Is 80 high? That seems totally fine.
- 3y ago

gregschlom 3y ago

> so the tube stays in your arm and your skin under the monitor remains broken That's not how it works, at least for the Freestyle Libre 3. The cross section of the needle has C shape rather than a O (technically I believe it's called a cannula). When you remove the applicator that C shape allows the needle to be removed through the hole at the top of the sensor, and only the flexible filament stays I your arm.

rnewme 3y ago
I belive he called the flexible filament "tube" and that you are both saying the same thing. Ie skin stays open (albeit in very tiny spot where the filament is sticked in)

barbazoo 3y ago

What symptoms would one have to present for an "online prescription mill"/"virtual care provider" to prescribe a CGM? I'm fascinated by this and would love to try it out but I don't want to bother my family doctor with this.

CaptainNegative 3y ago
The only symptoms needed are a pulse, the ability to type out a credit card number, and availability for a sham phone call. It's virtually impossible to not get prescribed one from a mill.
- EasyMark 3y ago
  How much would a month or two cost me if it was out of pocket? I wouldn't mind doing it for science.