Libre Sensor 2 - PLEASE BE CAREFUL - Recent Issues

[domoboy]

BACKGROUND: I've been using the libre2 sensor on prescription for well over 2 years now with no issues (apart from two falling off, and one telling me it had malfunctioned a week into it's life). On the rare occasion I have calibrated my sensor with a finger prick it has been usually either spot on or within 0.5, even during periods of transition. Not even the 15-30 minute delay has caused any issues. My Diabetic team at the hospital (UK, been a T1 since the age of 7 and now nearing 30) advised finger pricking isn't really necessary even to calibrate, even when driving as the DVLA accept CGM machines as accurate now, it's only if you are in hypo or exhibit symptoms you must test which has never been the case for me as I get really good warning signs.

My sensor ran our on Friday night, so I replaced with a new one. For the last week my BS readings have improved on normal, especially overnight which I attributed to a change in Glargine.

On Sunday afternoon (yesterday) my Libre was showing me as 3.4. Odd I thought, I felt fine and usually once I go below 4.5 I start to get the feeling of dropping and get a bit sweaty and just general yuck feeling. Anyway, I had some glucose and some carbs and 30 minutes later my Libre was showing as LO... weird, I had a little bit more glucose and then 10 minutes later I was showing as 6.4.

Great, I thought. Here comes the bounce. I decided to test 15 minutes later so I could begin and gauge how much novorapid to microdose through the bounce and it was showing as 4.2.... 5 minutes after that? 3.6 again. At this point I finger pricked to show 11.4. I then decided to monitor over the next 5 hours and do regular finger pricks and Libre readings. I have enclosed these on the image.

In summary, these were off anywhere between approx 2.0 mmol and 11mmol. I removed the sensor, and put a new one on as it was clearly faulty. I even switched arm.

I then did the same with this monitor (but not written and recorded) about 12 hours after starting it and it was anything between 0.1 and 1.5 in difference to a finger prick. No issues with that, seemed the norm. Then this afternoon (just after 24 hours had gone) the same differences as the other Libre started to occur. These are also on the image attached. Please note these readings were only taken during periods of questionable readings from the Libre and purposefully was selective in the amount of insulin given to make sure it wasn't a very big delay being the cause of issue for the ''test'' and my readings are usually nice and settled and lower than the finger prick results!

My sensor then failed and said there was an error and I needed a new one. I also use Glimp every now and then so I've recorded the levels from that, as I was wanting to make sure it wasn't a Libre app issue, or me, or the sensors themselves.

I've contacted Libre who have sent out replacements, but i am perplexed and now have some serious trust issues! The cherry on the cake is I leave for a beach holiday on Friday and whilst I was going to take my finger prick with me, was looking forward to practically hands free monitoring from the poolside! Has anyone ever become immune to Libre sensors?

UPDATE: The replacement sensors from Abbott have arrived. 2 hours in and I haven't left between 6.0 and 6.8 on my libre app, yet between 4 different finger prints I've ranged betwwn 8.5 - 10.7. Not looking promising. The auto CGM is also turned off for some reason on the app for this sensor and doesn't seem to be on, I will post an updated spreadsheet later with the disparity with this one.

 

[Westley]

The Libre has been a huge help for me in achieving better control, but I never fully trust it, and strongly disagree about the advice that finger prick checks are unnecessary.

I've had some sensors that give crazy false low readings in the first day or 2 then settle down, others that work fine then start getting slightly less accurate towards the last few days, some that stay consistently shifted a few units up or down, and some that just give nonsense and have to be removed.

Still, I'd say over 90% have been plenty accurate enough to use for the full 2 weeks. I do extra finger checks over the first couple of days, and have found that if it behaves for that long it generally stays fairly accurate for the rest. (The exception being times I've knocked it enough to shift the filament without fully dislodging the sensor, which leads to a bunch of fake lows then having to take it off).

 

[In Response]

It is a shame that your Diabetic Team told you it is unnecessary to finger prick when wearing a CGM. This is definitely not the case: even Abbott advise to test with a finger prick at times.

CGMs have limitations that neither Abbott nor diabetes teams tend to share but these are repeated many times on the forum.

If you are using a CGM to dose potentially fatal medication such as insulin, it is important to TEST CGM READINGS AGAINST FINGER PRICKS at least when high and low, and a few times during the first few days when levels are stable and not high or low.

I would not put the fault at the feet of Abbott, it seems to me that your Diabetic Team misinformed you.

(Very off-topic but ... Nice Tatts!)

 

[becca59]

In agreement with @In Response poor from your team. I never treat a hypo/high without a blood glucose test. Luckily my sensors are very much in line with a blood test but I’m still cautious. When you say calibrate, do you jus5 mean checking on differences? Because unlike a Dexcom you cannot actually calibrate Libre.

 

[Westley]

In agreement with @In Response poor from your team. I never treat a hypo/high without a blood glucose test. Luckily my sensors are very much in line with a blood test but I’m still cautious. When you say calibrate, do you jus5 mean checking on differences? Because unlike a Dexcom you cannot actually calibrate Libre.

Not in LibreLink, but most of the unofficial apps like Glimp, Diabox, Xdrip have ways of calibrating.

 

[domoboy]

Thanks everyone,

I've been a T1 Diabetic since the age of 7, so when I went onto Libre about 30 months ago I was blown away. The main benefit being able to see the direction of travel simply by scanning after 5/1/15 minutes (I don't trust the arrows). What I will also say is that I get incredibly good warning signs for both low and high blood sugar, and this weekend was the first time I've ever had a low on the libre and not actually felt low! Hence why I finger pricked in that instance.

Yes I agree it's a shame thats the guidance I got! I shall calibrate (by this I mean, test my finger prick versus my Libre) a lot more often going forwards now. Especially for high and low readings, and probably at least once or twice a day anyway just for a comparison to ensure it's working semi-correctly.

I do however, still think there is an issue. Whenever I have calibrated in the past (which prior to the last few days, was probably only a couple of times a week) it's always been within -05, usually within 0.2 tbf, unless I've been going through a period of transition, in which case 10 minutes later the Libre has been within 0.5 still accounting for the delay. My hbac1 has also been the same as my sensor prediction for each one which makes me think it did used to be more accurate previously?

As you can see from the numbers, the difference between the finger prick and the Libre readings are showing fairly significant differences. I understand the MARD should be under or around 10% regardless of first day wear or not?

I've also been seeing a ton of complaints on reddit since the Libre 2 updated to a CGM, with a lot of people reporting inaccurate glucose readings and sensors failing. Someone's diabetic midwife on there has apparently also noticed a theme in the last few weeks and is raising it with Abbott due to their hospitals concerns with the sensors.

I've returned the two faulty sensors to Abbott for them to look at on their end.

Thanks again,

 

[domoboy]

UPDATE: Replacement sensor from Abbott

 

[In Response]

Was that on the first day or did you give the sensor time to bed in as frequently recommended?

 

[RoughcutAU]

Only diagnosed 2 years ago and only using sensors for 12mths. I never got out of the habit of Fingerpricks for dosing so use the sensor and fingerpricks 4 times a day. Usually they are within one 1mmol give or take when in range. I have experienced the odd dodgy sensor though.

Just as I type i have the opposite problem - libre says 4.1 fingerprick 3.5(just where my hypo awareness kicks in).

 

[domoboy]

Here are my readings today post 24 hour sensor. Clearly some issues here... thankfully my GLIMP has calibrated well.

I will reiterate again, no issues before the last week.

Screenshot-20230908-210606-2 hosted at ImgBB

Image Screenshot-20230908-210606-2 hosted in ImgBB

ibb.co

 

[EllieM]

Two thoughts
1) Do you know if the sensors were both from the same batch? Could be a reason for them both failing.
2)

Has anyone ever become immune to Libre sensors?

It is possible to become allergic to the sensors. I had to stop using the libre 1 because I became increasingly allergic to the sensor and after a while all sensors just gave me completely erratic readings. Abbott were very helpful and sent me numerous replacement sensors and even a new reader, but in the end I had to stop using the libre.



















i

 

[jonathan183]

Stopped using the Libre2 - I just never got sufficient confidence in readings to dose insulin and had a run of about 4 sensors failing to give sensible readings or failing early. I think its' either my body reacting to something about the sensor or the sensor reacting to something in my body ... Abbott sent replacement sensors but just would not discuss or provide any further information ... I still have 3 replacement sensors in their boxes which I will not be using

 

[Aj1981]

@domoboy Great post, I have experienced similar with my Freestyle Libre sensors.

I have been using them for over a year now, I do find them very useful with their updates so get real time info of where my BG levels are. However, I have been slacking on using the finger pricking, as I should do it bit more, especially at night time. I tend to have a Hypo every other night around 2am-4am. As I am in bed, I just scan the sensor once it sends the alarm for the hypo, then I just grab my Lucozade or chocolate then fall back to sleep lol

Few weeks ago, I did see that the Libre was showing 2.8mmol, but when I used the finger prick, it showed 5.6mmol, I did not feel any symptoms as I do when going into a Hypo, so I did not take Hypo treatment, just wrote a note on the Libre app so I can refer back to it if needed.

I am trying to be good and use the finger prick at night when the sensor alerts me of a Hypo, so think best course would be to do the finger prick and go with the reading the machine tells us when having a hypo, instead of the sensor.

The sensors are a good addition and support in our T1 journey, but the finger prick will always provide us with the correct reading no matter during the day or night, especially if you are unsure or questioning the reading from the sensor.

Hope you have a wonderful holiday!!

 

[Liftupjoe]

I have the exact same issue probably for 3 years I do not trust them but my diabetes team say I have to stay on them as it shows how my bloods are peaking ect.
I always do blood checks for injections and most the time they are 5 to 6 out every time
So annoying
I would never trust a sensor pod that gives insulin.

 

[oconnorbp]

BACKGROUND: I've been using the libre2 sensor on prescription for well over 2 years now with no issues (apart from two falling off, and one telling me it had malfunctioned a week into it's life). On the rare occasion I have calibrated my sensor with a finger prick it has been usually either spot on or within 0.5, even during periods of transition. Not even the 15-30 minute delay has caused any issues. My Diabetic team at the hospital (UK, been a T1 since the age of 7 and now nearing 30) advised finger pricking isn't really necessary even to calibrate, even when driving as the DVLA accept CGM machines as accurate now, it's only if you are in hypo or exhibit symptoms you must test which has never been the case for me as I get really good warning signs.

My sensor ran our on Friday night, so I replaced with a new one. For the last week my BS readings have improved on normal, especially overnight which I attributed to a change in Glargine.

On Sunday afternoon (yesterday) my Libre was showing me as 3.4. Odd I thought, I felt fine and usually once I go below 4.5 I start to get the feeling of dropping and get a bit sweaty and just general yuck feeling. Anyway, I had some glucose and some carbs and 30 minutes later my Libre was showing as LO... weird, I had a little bit more glucose and then 10 minutes later I was showing as 6.4.

Great, I thought. Here comes the bounce. I decided to test 15 minutes later so I could begin and gauge how much novorapid to microdose through the bounce and it was showing as 4.2.... 5 minutes after that? 3.6 again. At this point I finger pricked to show 11.4. I then decided to monitor over the next 5 hours and do regular finger pricks and Libre readings. I have enclosed these on the image.

In summary, these were off anywhere between approx 2.0 mmol and 11mmol. I removed the sensor, and put a new one on as it was clearly faulty. I even switched arm.

I then did the same with this monitor (but not written and recorded) about 12 hours after starting it and it was anything between 0.1 and 1.5 in difference to a finger prick. No issues with that, seemed the norm. Then this afternoon (just after 24 hours had gone) the same differences as the other Libre started to occur. These are also on the image attached. Please note these readings were only taken during periods of questionable readings from the Libre and purposefully was selective in the amount of insulin given to make sure it wasn't a very big delay being the cause of issue for the ''test'' and my readings are usually nice and settled and lower than the finger prick results!

My sensor then failed and said there was an error and I needed a new one. I also use Glimp every now and then so I've recorded the levels from that, as I was wanting to make sure it wasn't a Libre app issue, or me, or the sensors themselves.

I've contacted Libre who have sent out replacements, but i am perplexed and now have some serious trust issues! The cherry on the cake is I leave for a beach holiday on Friday and whilst I was going to take my finger prick with me, was looking forward to practically hands free monitoring from the poolside! Has anyone ever become immune to Libre sensors?

View attachment 63036View attachment 63037

UPDATE: The replacement sensors from Abbott have arrived. 2 hours in and I haven't left between 6.0 and 6.8 on my libre app, yet between 4 different finger prints I've ranged betwwn 8.5 - 10.7. Not looking promising. The auto CGM is also turned off for some reason on the app for this sensor and doesn't seem to be on, I will post an updated spreadsheet later with the disparity with this one.

After 50 years of insulin and 2 years of libre 2 sensor I've found sometimes libre can have problems. During this heat mine gave errors but corrected itself, but I still have my Accu-chek mobile which I have replied on for many years and still use for a check of mmol weekend at 1 am mine failed with 8 hours left before change . Not had any variation of large levels as you and I still bounce on many occasions get a good glucose meter for safety.

 

[Circuspony]

Glad it's not just me. Warnings being going off and I didn't feel like I was having a hypo and finger prick showed I wasn't.

 

[PatsyB]

Been wearing the libra for a while now and been looking at the readings and going by them had my bloods done yesterday and it added ten onto the readings so they not that darn accurate and here wa sm thinking I was doing good

 

[PBarks]

Please be careful about using a CGM and driving. The DVLA requirement is that CGM users should keep a finger prick unit in the car. If at any time the CGM shows that the blood glucose levels have fallen below 4 mmol/ml then you must stop and check the position with a finger prick test. You should not resume driving until your blood sugar has risen to at least 5mmol.

 

[RobertJ]

Glad it's not just me. Warnings being going off and I didn't feel like I was having a hypo and finger prick showed I wasn't.

I just had a crazy situation over night. I'd like to know what people think of this.

I put a new libre on yesterday morning. Before bed it said 2.9 but a finger-prick test said 5.9. A few minutes later the libre said 3.3, finger-prick said 6.3.

I just went to bed, assuming the libre was being inaccurate. I woke up this morning to a libre reading of 3.1. The graph showed a red, flat line all night. My blood test kit said 3.8, so I really was low.

Now I don't know if I was low all night for eight hours or not. To think what eight hours being low has done to my brain is terrifying. I do have a light headache.

 

[Westley]

I know what you mean. I've experienced this and it is scary not knowing what happened overnight. I've had some sensors give flat line low readings for 12 hours after applying, but then start working fine, and others that do this then never give sensible readings. I've had it with sensors started in the morning too, when I know I definitely wasn't actually low.
I'd give it a little longer while checking with finger pricks to see if it settles down, but if it's still way off after a few more hours, take it off and get a replacement.
I try and switch sensors in the morning now, so I have a while to see if they're working properly.

My understanding about permanent hypoglycaemic brain damage is that it takes really quite severely low levels, significantly below the thresholds we are taught to consider 'low'.

(I'm absolutely not advocating for ignoring lows. Preventing even modest lows is good for preserving hypo awareness, and even if it's not low enough to cause permanent damage, the temporary impairment can lead to accidents)