[jimrandomh]

I'm a T1 diabetic, have worked on open source diabetes-tech (OpenAPS), and have used a number of different CGMs (though not this one specifically). This story... does not make very much sense.

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.

[SkyPuncher]

> 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

This has been my impression. I briefly used an Abbott Lingo to help me understand some health issues I was experiencing.

It's always been clear to me (including in the app and documentation) that CGMs are an extremely convenient tool as a first line - but struggle in extreme circumstances. And, let's be clear, if you would generally know if your body is in one of these extreme circumstances. You'd probably be feeling like shit.

That's not to mention the device in question, the Freestyle Libre, is (to my understanding) by far the most popular insulin-dependent diabetes CGM available.

This article is equivalent to calling the Boeing 737 unsafe because it's had the most Full Lost Events while completely ignoring it's flown 238.84M flights (which is basically more than the entire rest of the list combined).

[lostlogin]

> This article is equivalent to calling the Boeing 737 unsafe because it's had the most Full Lost Events while completely ignoring it's flown 238.84M flights (which is basically more than the entire rest of the list combined).

You don’t get many people calling the MAX a good plane.

If you include in the count a new model which arguable should never have been allowed to be called the same plane, then yes, your prior good record looks ok. Over various generations the hull loss rate had come down to 0.18 per million flights while the MAX is at 1.48 per million flight.

[stavros]

How does this relate to the CGM analogy?

[cornholio]

Manufacturers update software periodically on these devices, so each new generation is a MAX to some degree.

[zwirbl]

It's a bad analogy, and the 737 MAX is a bad plane

[jfengel]

That is odd. A too-low reading would result in less insulin and a high blood glucose, which can be extremely uncomfortable but is not immediately deadly.

If it had read too high, it could result in an insulin overdose, which can indeed bring coma followed by death in fairly short order.

[consp]

Theoretical you can get a hyperglycemic coma but for that to happen you need continued and sustained high blood sugar in the way your toilet would smell like a sugar factory for quite a while.

[rzmmm]

In type 1 diabetes lack of insulin can lead to a condition called diabetic ketoacidosis which is deadly. In type 2 diabetes it's not usually possible.

[mikkupikku]

I have two elderly relatives that use CGMs and both are at a stage in life now where they really cannot be expected to exercise common sense. I am pretty sure they've both been using CGMs exclusively and haven't been using finger sticks, at least not regularly, and one of them has a very hard time even understanding that apple pies are filled with sugar. No real intuition for which foods have or don't have sugar.

If CGMs are so unreliable and need double checking, I am quite confident that many patients don't understand this, even if it was carefully explained to them by their doctors.

[mattmaroon]

Ok but then that would seem to absolve the manufacturer of liability. If you sell someone a hammer and they try to eat it the manufacturer isn’t liable for the damage.

[mikkupikku]

If the product is defective and misused when somebody gets hurt, I don't think the manufacturer is totally in the clear morally, or even legally.

[pixl97]

Cool, let's ban the product and kill thousands more people than they save.

Don't let perfect be the enemy of good when good is increasing lifespans and reducing bad outcomes.

[array_key_first]

I mean, you don't ban the product, we don't do this generally. But you do make the manufacturer change their language or advertisment.

[pixl97]

Have you ever read the book of papers that come with a CGM?

[mikkupikku]

Bro I'm not calling for anything to be banned, I'm responding to the sentiment that the story doesn't make sense because users of CGMs should know better.

[mattmaroon]

Is it defective if it tells you it may make mistakes and must be verified and then it makes a mistake?

[liveoneggs]

How does the CGM react after pie-eating?

[mikkupikku]

"I don't know why it went up, they had cake but I knew I shouldn't, so I had pie instead."

[maximegarcia]

Having high glucose levels won't kill you in the sort term, yes. But we cannot compare pre-diagnosis high blood sugar level (the body had that for months so it is accustomed to it) to the suddenty of it with cutting off insulin. In fact, things can spiral out quite quickly.

You see false low glucose figures, that last, you start reducing your slow acting insulin, you skip some fast acting insulin. Within 24h, ketoacidosis starts and you can start feeling nauseous. At some point, if you eat, you vomit. You are cornered: you don't have the carb intake to inject insulin, and you can't eat. Even worse, at some point, if you drink, you vomit, so you dehydrate, and it's a matter of hours to live. Shit happens fast, things can get critical is a few days.

Diabetes management is complicated, this is far from exact science, and having a good knowledge of everything is hard. I was already bitten by this cycle of nauseous feeling with slow acting skipped a few month after my diagnosis. I learnt to never ever skip slow acting insulin, even when blood sugar is through the floor. Prepare some apple juice and still go on.

I have Freestyle Libre 2, and it is quite a disappointing thing software-wise. I have to reverse engineer another app to get an API for my data, I have to go through Internet to get my blood sugar level (for a standalone display for example, so I can't make one that works "off grid", like... in my plane), they do sparse updates, they lag behind OS version by dizains of month for their apps, they have 10s of apps/websites, it is hard to understand. So I'm not surprised by poor bug management.

I wish some big names invest in a CGM device. Don't make it medical (even medical grade ones like Abbott & co say you have to check with a finger thingy device, so why bother), make it $500 one time plus $10-20/month, make it open about the data and you'll get everyone. Maybe no one want to invest because in 10/20 years Diabetes will be a thing of the past?

[pixl97]

>say you have to check with a finger thingy device, so why bother

So you don't die in the middle of the night.

I sometimes wonder when typing this if you ever remember life before a CGM?

[maximegarcia]

I did the finger only for one month at the beginning. I'm glad CGM exists despite the limitations.

[tuetuopay]

This checks out with what a diabetic friends told me as to why he does not really uses tech: he preferred to take the time to learn "himself" and recognize the symptoms, because of such issues.

I suspected he was paranoid, but thanks for the rational explanation!

[pixl97]

>and recognize the symptoms, because of such issues.

There are a few problems with this. I'm a T1D and your sugar level can change very rapidly and you can be near a critical situation before you feel it. Even worse is an issue after you fall asleep. Tell your friend you'd rather not find him dead in the morning.

[tuetuopay]

Well thanks for the warning. I'm pretty sure he still has the device for those situations (he's a bonehead sometimes but not stupid), and it's more likely that my recollection is more dramatic than reality. What I'm sure is, he does not actively use it for daily life and learnt himself.

[DrStormyDaniels]

One of the main uses of these technologies is precisely because some type 1 diabetics can become unaware of the symptoms over time either through chance adaption or over-exposure, for instance, hypo-unawareness.

[mexicocitinluez]

That's fascinating.

[officialchicken]

Not only that, but the symptoms for hypoglycemia do change over your life, so that what is felt today (e.g. excessive sweating, blurred vision) may be totally different in the future (e.g. confusion, tingling thighs). Or you lose that sense of feeling entirely and never notice a problem until it's way too late to easily remedy.

[drysine]

>If a brand of CGMs have an issue that sometimes causes false low readings

Not sometimes. "Over an extended period".

"Abbott Diabetes Care stated that certain FreeStyle Libre 3 and FreeStyle Libre 3 Plus sensors provide incorrect low glucose readings. If undetected, incorrect low glucose readings over an extended period may lead to wrong treatment decisions for people living with diabetes, such as excessive carbohydrate intake or skipping or delaying insulin doses."

Months of high blood glucose level can worsen patient's condition or if high enough even put them into hyperglycemic coma in weeks(?).

[0] https://www.fda.gov/medical-devices/medical-device-recalls-a...

[consp]

While true, you would have to ignore all other indicators for quite an extensive period of time. Like excessive urination and hypersensitivity being obvious ones. Not impossible but I have the strong sense there is more to this story than reported in the FDA disclosure.

[DrStormyDaniels]

Not true, the effect of high blood levels can be very unpredictable. Especially above a certain number - and largely depending on the basal insulin strategy of the patient, for instance long acting shots versus constant micro doses of short acting via pumps. In the latter case, an untreated high blood sugar could escalate in a matter of hours to a fatal level.

[RobotToaster]

It's not that surprising, a lot of people (especially doctors) will dismiss symptoms if "objective" tests show normal levels

[harvey9]

In EMS school I was taught "treat the patient not the machine".

[pixl97]

>incorrect low glucose readings over an extended period

I use the G7 and the directions say to always use a finger stick to celebrate the unit, especially at high and low readings.

Did these people also not see and endocrinologist to get things like A1C?

Diabetes is very unforgiving as you get older or are a fragile diabetic. If they were just dependent on the CGM alone then it's likely a lot of other mismanagement was already occurring.

[drysine]

>to celebrate the unit

Typo. Perhaps you meant to celibate.

[camdenreslink]

Calibrate…

[drysine]

People have forgotten the old joke((

"A new monk arrived at the monastery. He was assigned to help the other monks in copying the old texts by hand. He noticed, however, that they were copying copies, not the original books. The new monk went to the head monk to ask him about this. He pointed out that if there were an error in the first copy, that error would be continued in all of the other copies.

The head monk said, ‘We have been copying from the copies for centuries, but you make a good point, my son.’ The head monk went down into the cellar with one of the copies to check it against the original.

Hours later, nobody had seen him, so one of the monks went downstairs to look for him. He heard a sobbing coming from the back of the cellar and found the old monk leaning over one of the original books, crying.

He asked what was wrong.

‘The word is ‘celebrate,’ not ‘celibate’!’ sobbed the head monk."

[consp]

Muscle movement will cause different reading in mine. They are great for trend monitoring but not reliable for real values. ... Neither are finger measurements as in lower and higher regions they also differ quite a bit. But as usually more measurements by more different methods get you a better image.

[dazc]

I found having the monitor on my left arm results in a more reliable connection and consistent readings. This isn't just during the day either, so can't be explained by lifestyle patterns?

[belorn]

The FDA announcement make no statement in one way or an other about the cause, only that there is a problem with two monitor sensors under certain model numbers and serial numbers. It not a given that a single production batch include a multiple of model numbers and products. Assuming it is bad quality control of the chemistry is thus not supported by the FDA announcement.

It could be the software freedom conservancy assumed software bugs, with the same limited knowledge as the assumption being made here about chemistry quality control, so readers will have to decide which sounds more likely. The article do state later that "We also will probably never know whether this issue was in hardware or software... the public deserves to know the technical details ". We can make a favorable interpretation here that they acknowledge the possibility of it being software, hardware or QC. Making accident reports public information is a common step in other areas in order to allow people to learn from mistakes and produce better products.

I will add that blaming faults on human error has generally been shown to be a dangerous route when dealing with fatal accidents in all human endeavors. Correct training and behavior by patients can help to reduce fatal accidents, but one should always be careful to put blame here as a culture of blame generally produce more rather than less fatal accidents. Human-computer interaction is a complex subject and its very possible that the accident rate of those specific CGMs could have been reduced or prevented with better design, depending on what the issue actually was.

[carlmr]

>the possibility of it being software, hardware or QC

There's a certain overlap here. It's not completely orthogonal. Having worked on safety critical systems before a lot of effort is put into detecting hardware errors in the software. E.g. random bit flips, ALU hardware issues, RAM writability issues, hash check of the loaded software being ok, plausibility check with (partually) redundant sensors.

You can detect a lot of hardware/QC issues on the software level. While it's still a hardware issue, better software can sometimes at least detect it

[darkerside]

I agree with you that the Fundamental Attribution Error typically wins the day. If people are making a mistake, find the systemic solution. But, it's critical to include Education as one of the potential components. If false readings are always a possibility, the alternative to expecting people to double check results is that we don't allow devices like this on the market.

[pixl97]

>the alternative to expecting people to double check results is that we don't allow devices like this on the market.

Excellent, to avoid killing a few people a year, you've killed thousands.

If you're not a diabetic or if you have no medical experience around this kind of device, kindly butt out and mind your own business. Low blood sugar in the middle of the night is an immediately deadly condition that needs treatment or the patient can end up with brain swelling. It's also not a condition that will wake the person experiencing it up. Having a CGM blare and alarm has saved countless people and given them a far better life from better sleep, less anxiety, and not randomly dying while resting.

Every CGM comes with directions telling you to calibrate the unit often and do blood stick tests to ensure the unit is working properly. Any diabetic should also be under the care of an endocrinologist as it's a complicated and deadly disease with lots of terrible ramifications.

[Cipater]

They simply stated that that is the alternative. They did not say that that is what should be done.

[darkerside]

Thanks. It's frustrating to be completely misunderstood, and I appreciate hearing from someone who was able to follow the nuance.

[jongjong]

I'm not a diabetic, but even I was skeptical of the title "Seven Diabetes Patients Die Due to Undisclosed Bug"; this draws a very direct 1-to-1 association when in reality, we know that a death would be the result of multiple failures/oversights.

I thought this article would try to sell us on the benefits of formal software verification or something... Though of course, you can't formally verify complex human biology.

[FloatArtifact]

At the hospital we test the glucometers with solutions for high and low to make sure they're within spec.

[nimchimpsky]

as a T1D parent, agreed, this a nonsense article and shows the author has no real experience.

[darkerside]

Agree. The linked FDA recall said the 7 deaths are "associated", which could just mean contemporaneous. This article is written by a new diabetic who doesn't seem to understand the disease very well yet, and is sensationalist in its reporting (perhaps unintentionally). They are probably opening themselves up to a defamation lawsuit here and are certainly disseminating misinformation, sowing FUD in service of an agenda, however well intentioned.

I rarely do this, but I'm flagging the article in hopes of limiting its exposure to new readers.

[officialchicken]

The OP is hardly anywhere near as sensational as the latest AI generated github something-or-another typically posted here. I found the article extremely useful and would not be aware that it effected MORE THAN ONE product line. Please don't let @dang bury this IMO. If you have an alternative URL please post it!

[darkerside]

He's not intentionally sensationalist, he's just flat out wrong. An uninformed piece like this does not belong here IMO without heavy context provided front and center.

[Aurornis]

> This story... does not make very much sense

Agreed. This story is clearly pushing an agenda to an extreme degree. They spent a lot of time linking to different things and past stories, but the claim of having killed seven people gets almost no coverage in the story. Can we at least get a source to where they’re getting that information?

[jjulius]

> Can we at least get a source to where they're getting that information?

Fourth paragraph of the article, first sentence, the hyperlink text says, "the US FDA announcement". The link[1] contains the following under the heading, "Reason For Early Alert":

> Abbott Diabetes Care stated that certain FreeStyle Libre 3 and FreeStyle Libre 3 Plus sensors provide incorrect low glucose readings. If undetected, incorrect low glucose readings over an extended period may lead to wrong treatment decisions for people living with diabetes, such as excessive carbohydrate intake or skipping or delaying insulin doses. These decisions may pose serious health risks, including potential injury or death, or other less serious complications.

> As of November 14, 2025, Abbott has reported 736 serious injuries, and seven deaths associated with this issue.

[1]https://www.fda.gov/medical-devices/medical-device-recalls-a...

[K0balt]

Associated with and “caused by” or even “contributing factor” are very, very different bars.

Most deaths are associated with dietary factors. !== eating causes death.