Reliability of Libre 2

I’m using iOS 18.1.1 on an iPhone 15 pro with no problems.

I’m using iPhone 14 & iOS 18.0
Sometimes loses signal but I just turn Bluetooth off & back on again & it starts reading again

Yes, I have both Bluetooth and calibration failures, you're not alone!

Here's a thread with my sensor history (which I started recording to try to get a handle on what was happening): https://forum.diabetes.org.uk/boards/threads/cgm-log-how-long-do-they-last-why-do-they-fail.114108

I think calibration is an issue if you lack fat on your arms, there is a Japanese study in a research paper which indicates poor calibration for those who are so lacking! I was confused about the Bluetooth issue, but have recently tried to never scan the sensor manually with my phone aside from when starting it, and it seems to have prolonged the life of the sensors (it's early days mind you) - so this may be an issue with my phone cooking the sensors, which is apparently a thing that can happen with certain combinations of chipset/sensor (in other applications, not necessarily libres).

You may find your problem is the BT version on your phone not Libre.

My comms failures are not related to Bluetooth failing on my phone (which is Android fwiw), but rather the libre stopping transmitting - this can be demonstrated by using a BLE scanner, which happily shows the messages from a working libre, and equally shows there are no messages after they fail.

Melgar said:

I live in Canada and I am having the same issue. My provider is Bell so I don’t think it has anything to do with BT.

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BT here in context is Bluetooth rather than British Telecom! I prefer using the acronym BLE (Bluetooth Low Energy, which these sensors are) to avoid ambiguity. There is no reason why a different Bluetooth version will make any difference though. BLE was only supported from v4, so it will work or it won't. Certainly there have been reports of resetting phones and the like fixing problems with Libre sensors, however the sensors often come back on their own, so it's very hard to know whether resetting did anything or just wasted some time.

The method I use is to run a BLE sensor scanner, which shows me a list of all the BLE devices within ~50m (depending on their type and broadcast power) - it's surprising quite how many there are! The libre sensors don't transmit continuously, but if you watch/look at the recent history of the scan after running it for at least a minute (they should transmit a reading once per minute so I usually leave it for 5 to make sure there's not a clock drift error and to hopefully give the sensor a chance if it is suffering from an intermittent failure), you should see the libre appear. If you don't see any devices I'd suggest you may have a problem with the phone (so a reboot might work), but if it's just the Libre that does not reappear, it's pretty compelling evidence that it's the libre itself that is not working rather than the phone.

Under Android I use an app called "BLE Scanner" (I can dig out a Play link if anyone wants it), which is free. The Libres appear with a name that starts with ABBOTT and then continues with the device s/n. They don't appear to have a manufacturer specific "MAC" (not even the first section), so they may well be randomly generated (which is allowed afaiu and also now the convention for other devices such as Wifi.)

PeeBee12 said:

Hi, I have used Libre2 for probably a couple of years now but I am finding that the Bluetooth connection to my iPhone 8 is unreliable, and this problem seems to be getting worse. I am having to contact Libre support for something like 50% of the sensors I use. They are very good about it and provide replacements and ask that I return the defective sensor to them, however, they don't give any feedback, and when I asked if it could be an issue with my phone they seemed to say no. Taking a look around the forum here I don't seem to see any other reports of similar issues.

Do others have problems with Bluetooth connection with their Libre2?

My Bluetooth works fine with other Bluetooth devices, although I do sometimes need to turn off Bluetooth and try again. This doesn't work with Libre2. I am told that Libre2 Plus works the same way as Libre2 and so will be no different. Interestingly the sensor sometimes shows up in the list of Bluetooth devices as 'accessory' and sometimes it isn't listed at all (although it may still be working).

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Hi, I'm having exactly the same problem with my iPhone 8 which for at least the first year of using the Libre worked fine. Now, it is virtually every other sensor I put on which gives problems - it loses the CGM readout and if I have the signal loss alarm turned on it bleeps every 15 mins or so. I put on a new sensor this morning. It worked fine until I went out this afternoon and since then I haven't been able to view my levels without doing a scan. The bleeping of the alarm annoys my partner very much and the dog isn't too happy about it either. Abbott always try to be helpful; every time we go through the same routine of checking the settings on my phone and when all are seen to be OK, they give in and say they will send a new sensor. I have asked many times if others are having the same problem and the answer is always either negative or the person I'm speaking to doesn't know. I just wish Abbott would investigate, sort it out and let us know what the problem was.

@llandrillo switch the loss of signal alarm off on your sensor. Haven’t had mine on for years. I don’t need to be told it’s lost connection. I can see when I pick up to check.

Thanks @becca59 but I’ve tried that. If I’m busy, I then miss that I’m going low until it”s too late and that leads to the roller-coaster ride. No, I need the alarm, and as it’s provided I don’t think it’s unreasonable to expect it to work. Being unreliable is no good.

For the past 3 weeks or so, I've started getting these intermittent signal loss messages & alarms on my Libre 3. I have a Samsung A20 phone. The alarm beeps 7 times every time there's a signal loss. I've tried turning bluetooth on & off - this works at the time but has not stopped the regular frequency of the signal losses & alarms. In fact, they seem to be getting more frequent. The alarms are very annoying and sometimes embarrassing, especially when they go off in work meetings and pool matches - this is why I never have any alarms set to on.. I struggle to understand why this just started a few weeks ago. I have not contacted Abbotts as I don't think my sensors are faulty; I have just switched sensors and it has not made a difference. I don't know how to resolve this.

I've used Libre 2 sensors with the LibreLink app on both an IPhone 11 and an IPhone 13 (current phone I switched to back in February) for the past couple of years, the former running IOS 17.6.1 and the latter on IOS 18.2. Commonly with me, I tend to start experiencing problems with Bluetooth signal at least 24 to 48 hours after I've activated my sensors, which then happen intermittently throughout the remaining 12 days, usually getting more frequent the closer the sensor gets to the end of its life. Though, in my case, I think this is sometimes attributed to how often I scan my sensor every 24 hours (I tend to scan my sensor before my meals, before bed and every two hours after eating).

In terms of comparing how my sensors have been operating since switching phones, I haven't noticed any significant changes to my sensor readings alongside my fingerprick readings on Bluetooth. For the most part, the sensors seem to stay accurate throughout the 14 days, albeit with a good chunk of them being faulty and having to be switched out early (which has happened with both phones). Although, I have noticed with my recent sensors that my signal errors have been prolonging for more than ten minutes. Usually when I get a signal loss, I switch my Bluetooth off, wait twelve minutes, and then turn it back on and scan again, which restores the signal. Since starting my new phone, however, some of my sensors have been taking longer than twelve minutes to regain connection, forcing me to repeat the process at least three to four times before it reconnects. This was something that didn't happen with my old phone, but I'm not sure if it is a phone issue or a sensor issue. My luck with the Libre 2 sensors hasn't been great lately... My GP did recently switch my repeat prescription to the Libre 2 Plus sensors, so I'll probably find out which it is once I've gone through the last of my Libre 2 sensors and have to order some more.

Either way, signal loss with Bluetooth has always been common with my sensors between both phones, so I think in my case it's more to do with the sensors than the phones themselves.

I phone 12 mini here and using latest IOS 18.4 no problems saying5hat haven’t really had any problems apart from the odd sensor stopping working, I too have turned the out of range alarm off as I don’t tend to have my hone strapped to me if I say go for a pee or if its charging etc , I still use my low sugar alarm which i set at 4.3 as soon as it goes off I take sugar that way I don’t get a hypo and as my Libre is a few points lower in reality it gives me some leeway . I find Libre a great system it has its idiosyncracies but I can remember a time when I had to try and control my blood sugar with out taking my blood sugar how does that worK???

I was told by Abbott that my iOS was too new and that the device has not been approved with that version.
The last two sensors have failed and I’m getting replacements but I really am worried about not getting an alarm especially when I go to bed.

SimonP78 said:

My comms failures are not related to Bluetooth failing on my phone (which is Android fwiw), but rather the libre stopping transmitting - this can be demonstrated by using a BLE scanner, which happily shows the messages from a working libre, and equally shows there are no messages after they fail.

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Nice to read that I’m not the only one with this problemm. It’s so annoying. My other issue is my average reading according to the sensor are higher than my actual readings

The signal loss is driving me mad! Never been good since I first started using the sensors back in January of this year but now I’m recording signal loss on average 14 times a day and through the night it just fails to connect! Really frustrating that what should be a life saving device isn’t working properly.