CGMs (of any brand) are not, and have never been, reliable in the way that this story implies that people want them to be reliable. The physical biology of CGMs makes that sort of reliability infeasible. Where T1s are concerned, patient education has always included the need to check with fingerstick readings sometimes, and to be aware of mismatches between sensor readings and how you're feeling. If a brand of CGMs have an issue that sometimes causes false low readings, then fixing it if it's fixable is great, but that sort of thing was very much expected, and it doesn't seem reasonable to blame it for deaths. Moreover, there are two directions in which readings can be inaccurate (false low, false high) with very asymmetric risk profiles, and the report says that the errors were in the less-dangerous direction.

The FDA announcement doesn't say much about what the actual issue was, but given that it was linked to particular production batches, my bet is that it was a chemistry QC fail in one of the reagents used in the sensor wire. That's not something FOSS would be able to solve because it's not a software thing at all.

I've been a type I diabetics for over 25 years and I don't quite understand this one. Low blood sugar is an immediate life or death situation, but high blood sugar killing people? Just how high was it and for how long?

As someone that has a CGM I still calibrate it by using a blood test every couple of days because the CGM sensors can wander on accuracy.

I like the technology, but you have to 1) know your own body and 2) verify if you are uncertain about the readings. Every time I've switched devices I've interacted with diabetes educators, and they pretty much always tell me to always be prepared to verify manually (with an old-school finger stick and test strips).

Additionally, it's not always the fault of the technology, but often where meatspace and technology interface. When you insert a CGM, there's always a risk of the canula not going into the skin correctly. (usually it's a spring-loaded insertion tool and shoot a needle into your skin quickly, but it can mess up if the amount of pressure applied is wrong etc) In such a case, the sensor that measures your blood will often, where you can't see, sit on top of the skin. This results in insanely low readings. That happens to me a few times a year (I swap out the sensor every 10 days), and you have to listen to how your body feels relative to the readings, and replace the sensor if necessary.

[1] https://abbott.mediaroom.com/press-releases?item=124718

For high glucose you inject insulin, but if you don't really have high glucose you end up with dangerously low levels leading to coma or death.

https://www.bfarm.de/SharedDocs/Kundeninfos/DE/10/2025/42777...

It's a stretch to go from "associated with 7 deaths" to "killed 7 people". These devices are worn by millions. So coincidental deaths will happen irrespective of causality.

Would be good to have more details on the cases. Kind of hard to see how low readings would cause deaths. You eat, then notice things don't go up, then do a finger stick test and notice it's off.

To die you'd have to end up with ketoacidosis - there are ways to notice. Sure it's bad to have falsely low values but very unlikely to kill.

If one wants to separate the hardware (insulin pump, CGM) from the algorithm that controls them, seems like Tidepool is one org to talk to.

I (a non-diabetic interested in athletic performance) use an Abbott CGM sporadically and I have absolutely not agreed to any terms of service nor any other agreement of any kind - legal or otherwise.

I bought a purpose-specific, old model iphone from "Back Market" with no SIM card, very briefly allowed it wifi access long enough to download the "Lingo" app, then set the phone to airplane mode. Dedicated, throwaway email and AppleID.

It has never left airplane mode and it works perfectly. Pairing subsequent sensors does not require taking it out of airplane mode.

Further, I have no legal relationship nor have I made any agreement of any kind with Abbott.

I highly recommend that any user of these devices do the same.

I bought one of these monitors for fun, because I wanted to see how my blood sugar reacts to different foods. The freestyle libre 3 plus.

After wearing it for some time I woke up one morning to sky high blood sugar, talking 13+mmol/l. My manual measures showed around 4.9mmol/l.

The device was essentially not functioning anymore. I sent the company an email, filed out a report, returned the device and received a new one in the mail.

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

Beth McNally & Amy Rush - 'TCR in Practice: Navigating Insulin for Protein & Fat in Type 1 Diabetes'

At the end of the video there is some strategies described with automatic pumps.

And the graph a t=174 is kind of eye opening:

https://youtu.be/uHaYPEDGaro?t=174

> > Abbott Diabetes Care stated that certain FreeStyle Libre 3 and FreeStyle Libre 3 Plus sensors provide incorrect low glucose readings.

My understanding is the problem is probably the same, or likely related to, the pressure low - where basically if you eg lie down on the side of the sensor, it can produce a false low sugar reading.

Presumably, this could push some (already sick) people towards DKA. DKA can go from "slightly bad" to "crazy bad" in a span of hours. (Don't, or do ask me how I know.)

Add in reluctance of people to go to the hospital in the US, and I can totally see how people might've died because of it.

It's a bit of a swiss cheeshole/perfect storm - poor BG management, likely not well enough to afford a hospital, possibly already sick - and unfortunately I'd imagine economically struggling people are likely to have a significant overlap of many of these at the same time. Tragic, but realistic, given the sheer scale of many people use these devices.

Any diabetic person must have heard and read this recommendation a thousand times.

The actual scenario to worry about is if the number is too high and a close loop system make so the pump injects too much insulin.

On one hand, this is a very, very bad bug. On the other, the article is almost of hit job to try to prove FOSS would have solved this issue. There are also a lot of completely factually incorrect statements and wild assumptions.

If my understanding is correct, the device in question, the Freestyle Libre 3, is the most popular continuous glucose monitor (GCM) in production. And, one of only a few approved GCMs available. By the very nature of being an extremely popular device that helps manage a chronic, high effort disease (diabetes management is a massive, massive mental drain) - you're going to have failures.

Not to mention, I've always been under the impression that GCMs have some faults and IF the device reports do not match your expectations, you should confirm with an alternative method (like a finger prick) or seek emergency medical attention (which should have been sought in these extreme circumstances, anyways).

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Here's the thing for me. FOSS essentially assumes that the user is going to be willing to understand the underlying details to know when FOSS fucks up. Yes, when FOSS fucks up. That's simply not realistic for any consumer product. If your argument for FOSS relies on users being able to read raw data and interpret things that are only learned by education, that's not a consumer grade solution.

Anecdotally, I used use Abbott's Lingo CGM a few months ago to help get me more data on a health issue I was having. I would never, ever, in my wildest dreams have trusted FOSS to get this right. There's simply too much money/effort/rigor involved in getting these biomedical devices correct to believe that the FOSS community could simply create a better product without actually doing any trials or studies. Not to mention, the recommended app (Juggluco) has a terrible UI. This just isn't going anywhere.

To be clear, this is a deadly bug and Abbott should be held accountable - but claiming the solution is some untested, untrailed, terrible UX is not the answer.

I'm struggling to understand how occasional false low monitor readings would cause any significant problems?

FOSS can be written the same as any other software, and there's plenty of FOSS that fails to meet modern best practices.

But a software building code might have saved lives. The same way building codes save lives around the world every day, by ensuring safety-critical things in the world aren't slapped together haphazardly, and are tested for safety.

Ask your representatives in government to assemble a professional body to set software building codes for the software that could potentially kill you.

And I'm glad the text agrees

> It's hubris for activists to guarantee that harm would be prevented if Freestyle had publicly released the hardware specifications and the complete, corresponding source code (CCS). FOSS isn't immune to bugs — even dangerous ones

> We also will probably never know whether this issue was in hardware or software

That being said

> Specifically, the bug caused the device to falsely report an extremely low glucose level

Aren't people cross-checking this with how they're feeling?

People on low glucose won't be feeling normal. If you really had an abnormally low reading maybe double check with a strip meter and calibrate with how you feel

Medical devices are hard. There are hundreds of variables causing variations in measurement

> As a public policy and public health matter, the public deserves to know the technical details (software and hardware) of both the functioning device and the failed device

Yes. 100% this

(I'm all for OSS for reading calibrated data and processing it the way you prefer of course)

My wife is a T1D - you’re either diabetic or not.

Freestyles are not reliable to be used purely for managing immediate levels of glucose - it is more about trends and give an idea of whether it is going up or down.

This appears to be an education issue, for the users and also for the writer.

1. Insulin helps get sugar into cells. Glucagon gets stored sugar out of the liver into the blood. Diabetes management in 2025 only deals with supplying external insulin.

2. There are several variants of diabetes. Type 1 is an autoimmune disorder where the body attacks the cells that make insulin.

3. Too much insulin equals all the sugar getting sucked out of your blood and lymph and into cells. This is really bad in an acute way. Your brain cannot run without sugar. Accidentally give yourself too much insulin for the sugars and wind up dead or in a coma in short order.

4. Highs are also bad, but generally in a less acute way. There are exceptions, but being too high with blood glucose for a period of time doesn't have the acute risks of being too low. Diabetics (or their caregivers) carry around quick absorbing sugar sources to help against a low.

5. The peak action (fastest reduction in blood glucose level) of the common insulin, in the way we dose it, peaks 90 - 120 minutes after the dose. The long tail is about 5 total hours of action from the point of dosing. So you should give insulin in advance of when you expect digestion to move glucose into your bloodstream. This is tricky. Also, as insulin ages, the peak of the action happens later. If a new vial is 90 minutes, an nearly empty vial might be 120 minutes after dosing for peak action.

6. CGMs, the on-body instrument in question here, are both flakey and amazing. There's a novel of good and bad here. I'm glad they exist, they can be cantankerous. They are a tiny potentiostat, if that is something you happen to be familiar with.

7. Very high blood sugar is treated with extra insulin to overcome the osmotic pressure of having too much glucose in the bloodstream. There's also a lot of chemistry here (glycocalyx to get you started). If your blood sugar is high you generally need more insulin to get past the hysteresis effects. Once the blood sugar starts to come down, that extra insulin is still around, and can cause a dramatic low. CGMs let you observe this, and "catch the low" by eating sugar to replenish the baseline sugar trapped in circulation.

8. Diabetes management is challenge every day, multiple times a day. Especially with small child who doesn't communicate to you about what they believe about their blood sugar. This is my personal circumstance.

9. Endocrinologists have suggested some wild stuff to my wife and I. For instance, keep a tube of cake icing around, as you can administer it rectally to a child who is passed out (or worse) from a deep low blood glucose. This is how poor the standard of care can be.

Father of 4.5 YO son with Type 1 diabetes, and materials engineer by education.

I bet almost everyone with a device with that bug was injured more or less, because high blood sugar is a silent damager of many organs resulting in cumulative damage without overt short term symptoms of injury. For example, slow damage to eyesight, kidneys and nerves in the feet.

I've always been suspicious of the yahoos writing the software that controls these kinds of devices being a security guy and all.

But I also would love to participate in, contribute to or help in any way with reverse engineering, open sourcing, or in some other way making it so that my wife's life isn't dependent upon the quality of software developed by the lowest bidder they could outsource it to.

If anyone knows how I could help please let me know who to reach out to.

Learn about type 1 diabetes to understand why this distinction matters.

Type 1 diabetes is not caused by food or weight. It results from an autoimmune reaction that completely destroys insulin-producing beta cells. No one understands what causes type 1 diabetes, but generally it's believed to be caused by viruses and infections. Sometimes you can read about "genetic factor", but overall majority of people with type 1 diabetes have no family history of this disease.

The incidence of type 1 diabetes has been increasing in many countries, and researchers do not yet understand why. It most often appears in children and young adults and currently has no cure.

Once again: type 1 diabetes appears to be random and has no cure. It's not caused by food or weight in the slightest. And your life (of life of your child and yours too) suddenly becomes an absolute living hell. Think about it for a second.

For some unknown reason public awareness of type 1 diabetes is hugely limited compared with other incurable diseases. For example, in the UK more people live with type 1 diabetes than with HIV, yet until someone is directly affected, they usually know nothing about this disease. It hits them like a train.