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Comment by georgebarnett | Hacker News Reader

The device claims to have 97% of reading within 15% of the Freestyle Libre, which itself is then not as accurate as blood glucose.

Put another way, it’s less accurate than a device that’s already less accurate than finger sticks.

Given this info, I’m not sure this version is practically useful yet in terms of accuracy.

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Hi, this is actually my field of expertise! IdealMedTech is a clinical glucose control startup targeting inpatient glucose control.

Having an MARD (mean absolute relative difference, or in math terms, E[|g-r|/r], g is measured glucose, r is reference glucose) of below 15% is actually considered very good for glucose monitoring.

We did a study that involved modelling different levels of sensor error, and you actually start to see diminishing returns on control once your MARD passes below 10%, with 15% being a good target.

Most sensors on the market that are considered best in class (eg Dexcom G6) have guaranteed MARD below 15%, usually sitting right at 10%. Getting lower than that is very difficult for interstitial glucose, especially using the classical glucose oxidase sensing mechanism.

There are other ways to sense glucose using, for example, Raman spectroscopy, and there have been companies successful in employing these techniques (OptiScan comes to mind), but I'm not yet convinced by the capacity of spectroscopy to deliver accurate results in the presence of interference from drugs and perfusion issues.

In addition, I imagine confounds which are patient/location specific can be calibrated out to some extent, by comparing against finger-stick while fasting, and longer-term A1C.

Following a chain of references from the OP:

study of wearable: https://cb195ec0-5419-4138-91fc-7288f69116ec.filesusr.com/ug... whitepaper announcement: https://medium.com/know-labs/know-labs-releases-white-paper-... whitepaper: https://docs.google.com/document/d/e/2PACX-1vQXqlmKwPzhZIn9t...

The whitepaper gives actual prep methods for tissue phantoms. It shows a clean correlation of ca 1.72GHz transmission to glucose. Presumably altered parameters in tissue phantoms could help roughly characterize confounds.

> Most sensors on the market that are considered best in class (eg Dexcom G6) have guaranteed MARD

Disclaimer: I work for Dexcom.

A few times every year, there's a ton of hype about some new noninvasive device, and the newbies get a bit worried, but the old timers just shrug it off.

We (humanity) will literally be able to regrow new pancreases with stem cells before we have accurate noninvasive blood glucose devices. Even Tim Cook with unlimited resources at his disposal admitted it's a much harder than they thought.

That said, I think there's a large market for people without diabetes who are interested in their blood glucose and who may not need super-accurate readings. For example, as a long distance runner, it'd be super helpful to know if my blood sugar is trending down before I bottom out, so I can know when to eat a gel pack, etc. It would also be useful for people trying to lose weight to learn how their eating habits and exercise affect their blood sugar levels.

Noninvasive devices may be better for this group of people who don't need the devices to be accurate enough to make decisions about insulin-dosing.

"A few times every year, there's a ton of hype about some new noninvasive device, and the newbies get a bit worried, but the old timers just shrug it off"

This.

But a buddy of mine may surprise you soon. And I worked in the field too.

And a lot of people are waiting to be (surprised). It super duper helpful for t2dm folks to know the "trend" - which food works better, which food doesn't, is the medication working, how much workout is required to drop the blood sugar levels, the dawn phenomenon etc.. with literally billions of people getting affected with t2d it would be a game changer. Still hoping for apple watch xx to have that feature.

Thank you for your work. My 9 year old son has worn a Dexcom for the past 3 years (Medtronic prior to that) and it's a godsend to be able to pair it with Sugarmate.io so we get phone calls in the middle of the night if his BG goes low.

This... brought back some memory...to average or not to average... C8 Medisensors achieved better weekly MARD in the early 201*. But the problem was, on a bad day, no one knows why it was bad..., so no way to alert the user (unless the reading was way off). Even though on "average", performance looks nice, but a bad day the data can be very problematic for a user, and the user has not way to trust the device based on MARD...

This is a great point, and precisely why we're using two sensors and a simple voting algorithm in our first in man trial (3+ sensors and associated algorithms were deemed too risky by FDA for initial studies).

Not sure what sensors you are using... why FDA thinks more sensors carry higher risk?

It's not the number of sensors, it's the novelty of the voting algorithm required to fuse those sensors that gives them pause. FDA likes to be _VERY_ conservative when it comes to trying new things. We're trialing our control software, which is already novel to them, so anything we can do that's not brand new helps reduce our risk.

More information should help make more informed devision, if the algorithm can not clearly explain it to FDA or FDA cannot understand that is the case... something seems wrong here... all the best wishes and also encourage more exploration.

Patients averse to finger sticks are going to use this much more often. It's going to provide more useful data to them. Much of the time the exact number isn't as important as knowing the trend or the general range.

Whether this makes more sense than a Libre for someone just depends on price and how insurance treats it.

I tested my blood sugar when my wife was pregnant and she was testing hers. I was amazed at how just from the small blood stick, and even if I had my wife do it and didn’t see any blood, I’d get sick to my stomach every time I did a blood stick. I’m glad I don’t have diabetes or I’d have a terrible time of it.

Yes, it's not fun. On top of that, for a permanent diabetic, finger sticks over a long period of time are an infection risk, especially if the patient isn't good at using all of their fingers (I got comfortable with it and there were still at 4-5 finger locations that I dreaded pricking.)

A completely non-invasive device even getting close to the accuracy of finger stick or implanted devices is a big deal.

Agreed, as a diabetic and climber I've used a lot of the libre pucks but honestly, there is no spot on my body I wont use while practicing my sport. Still the libre was miles better than always pricking my fingers and arms.

I've been thinking about what kind of EM-signal could be used for this for a long time, IR-spectroscopy never seemed possible. But this has real potential.

I worked on the Freestyle Libre, I’m thrilled to hear it’s at least a workable solution for you. When I was working at Abbott, I often volunteered for testing finger-stick devices, which made me appreciate a small part of what people with diabetes have to endure.

I've used them and they're great just pricey

I use a Freestyle Libre sensor and I like it better than finger sticks. When I was doing finger sticks I was averaging 4 tests a day; before each meal and at bedtime. With the Freestyle Libre I'm checking my glucose an average of 20 times a day. But the Freestyle Libre sensors are quite expensive. I have insurance so my out of pocket expenses are very low, but my provider bills $1074 for 2 sensors, which last for 4 weeks.

I have read comments from other posts that buyers without insurance can get sensors for substantially less, but they are still quite expensive. When I was doing finger sticks I could get enough test strips for a month for about $30.

Your provider is being ripped off, I'm pretty sure my doctor is not selling them subsidized and I'm paying roughly US$62 each.

I still find it quite expensive but it's acceptable with my income and taxation where I live.

What country?

The provider bills for $1074, but their actual reimbursement is only $208 for 2 sensors.

I am deeply grateful for your work and that of Abbott. The Libre has been life changing for me, possibly ever more so than getting a pump as it gave me a much clearer picture how my body reacts to different foods, exercise, lack of sleep, etc.

After about two years of usage I have encountered very few issues at all. My only complaint was that I would like to scold whoever crippled the sensors and readers somewhat by making them region specific for what I can only assume are purely market control reasons (not to mention that this is not obvious from the packaging or instructions from what I can tell and I only found out when talking to an Abbott representative that cautioned me that readers and sensors were not compatible between regions).

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