Libre 2 Sensor Accuracy

[Eternal422]

I have only just started with Libre 2 and initially really impressed with everything, loving the ability to scan whenever and wherever I want easily. The Libre readings were fairly close to finger prick BG and I fully understand the lag and variation between BG and ISF readings. With nice, stable BG, the Libre was within about 1 mmol/l, so totally acceptable and I was happy to base insulin dosing decisions on it. The initial daily graphs were all roughly similar and showed mealtime spikes with readings close to the finger prick tests.

Then after about 4 days I started getting overnight lows of around 3.6. Ok, I thought, possible and something I would never known anything about as there’s no way I would wake up and do regular finger prick tests. But at 3.6 I would definitely be feeling the hypo and I wasn’t. The finger prick was 5.8, so the Libre was just over 2 mmol/l lower. The day continued with a daily graph that looked totally different to the previous initial days, showing always around 2 to 2.5 lower than BG and much flatter, no mealtime spikes anymore. I have even had the Libre reading 3 to 4 lower when BG was otherwise stable and not changing between finger prick tests.

So, I have called Abbott and they are sending out a replacement sensor without really any explanation other than perhaps the filament was bent from the sensor. Not sure why it would initially be ok and then fail, but I suppose there are lots of variables and maybe it’s my body acting odd in some way with the sensor filament?

I have since googled about this and come across lots of reports of inaccurate or failed sensors. But I guess human nature makes us complain more often than praise, so I’m hoping that there are a higher number of people with positive experiences and that overall the device works well?

I so much want this system to work and be accurate enough to base insulin dosing decisions off. I would be very interested to hear about other people’s experiences with the Libre.

 

[nonethewiser]

Find libre 2 very accurate have done since making switch about 2 years ago, do occasionally check accuracy & it's always near enough match to bg readings. Do bolus from libre results so have full confidence in it.

 

[trophywench]

Nowhere did anyone promise that Libre would match BG 100% of the time. Overnight though, they do warn us upfront that 'compression' lows are much more than possible. So it's perfectly possible that you had compression lows. It matches better when BG is between 4 and 10 and should it wander above or below, it's anyone's guess how well it will match.

Also most of us find that inserting the new one 24 hours or so before the old one dies, usually means the new one is more accurate from when we start it the next day. Just gives it more chance to get used to our own body make up and chemicals is all. Dunno why precisely in strict scientific terms - but it just seems to work is all. Took me a while to decide to adopt this practice but on the basis of 'don't knock it till you've tried it' - I tried it and blow me - it worked.

 

[Eternal422]

Find libre 2 very accurate have done since making switch about 2 years ago, do occasionally check accuracy & it's always near enough match to bg readings. Do bolus from libre results so have full confidence in it.

Thank you, that’s really encouraging. Looking back over the graphs tonight it seems to be roughly 2 to 2.5 lower, so I could live with that. I’ll need to give it longer over more sensors to see if it works for me, but so hoping that it will as this feels like a game changer.

 

[Bruce Stephens]

I’ll need to give it longer over more sensors to see if it works for me, but so hoping that it will as this feels like a game changer.

I find it's usually OK (within about 1 of a test strip) but some sensors are worse than others. (And I had one that just gave up.) Some people (for reasons we don't know (though Abbott may, for all I know)) find it doesn't work for them.

In which case there should now be the option of Dexcom ONE. (Similar price, now can be offered by GPs just as Libre is.)

 

[Eternal422]

Nowhere did anyone promise that Libre would match BG 100% of the time. Overnight though, they do warn us upfront that 'compression' lows are much more than possible. So it's perfectly possible that you had compression lows. It matches better when BG is between 4 and 10 and should it wander above or below, it's anyone's guess how well it will match.

Also most of us find that inserting the new one 24 hours or so before the old one dies, usually means the new one is more accurate from when we start it the next day. Just gives it more chance to get used to our own body make up and chemicals is all. Dunno why precisely in strict scientific terms - but it just seems to work is all. Took me a while to decide to adopt this practice but on the basis of 'don't knock it till you've tried it' - I tried it and blow me - it worked.

Thanks for your comments - Abbott didn’t say anything about compression lows but I have since read about them. I have tried to at least start off sleeping on my back or opposite side to the sensor, but where I end up during the night is anyone’s guess so it could be the reason for the overnight lows!

I appreciate the differences and lag between BG and ISF readings, but even so this sensor was roughly what I expected but after the first 4 days is now pretty consistently 2.5 or sometimes more lower than BG even when BG is stable between finger prick tests.

Abbott are sending a replacement sensor anyway, so I’ll see how I go as time goes by. I’d also seen the bit about inserting the new sensor 24 hours before activating it and can well believe it allows the body to settle down with it so to speak before you take readings from it. I suppose there are differences if the filament hits a blood capillary, lands in a fat cell or bends slightly! So many variables, but I do keep coming back to the fact that they must be reasonably accurate otherwise they would never have been approved!

 

[Eternal422]

I find it's usually OK (within about 1 of a test strip) but some sensors are worse than others. (And I had one that just gave up.) Some people (for reasons we don't know (though Abbott may, for all I know)) find it doesn't work for them.

In which case there should now be the option of Dexcom ONE. (Similar price, now can be offered by GPs just as Libre is.)

That’s good to know, hopefully my body will start behaving with these sensors, but I didn’t realise the Dexcom was a possibility if for whatever reason the Libre doesn’t work for me.

 

[Bruce Stephens]

but I didn’t realise the Dexcom was a possibility if for whatever reason the Libre doesn’t work for me.

I think it's only just become available.

 

[Elizabethe]

I banged my arm again whilst on a caravan holiday, the sensor stopped working with three days to go. I put on my spare one as travelling home. And what a nuisance just now reading 11.3 but finger prick days 7.6. It has been like this all day, like trophywench I usually put the sensor on at least 24 hours beforehand, so hopefully it will settle by tomorrow. in the past two months I seem to be having more issues with the Libre2.

 

[Eternal422]

I banged my arm again whilst on a caravan holiday, the sensor stopped working with three days to go. I put on my spare one as travelling home. And what a nuisance just now reading 11.3 but finger prick days 7.6. It has been like this all day, like trophywench I usually put the sensor on at least 24 hours beforehand, so hopefully it will settle by tomorrow. in the past two months I seem to be having more issues with the Libre2.

That’s a real nuisance! As you can only get 2 sensors per month on prescription I’m wondering about buying one to have as a spare for situations like you mention. Even after just 4 days of it working well I feel lost now without it! It seems to be getting worse and now reading almost 4 below BG and so showing me in hypo territory for lots of the time! Can’t wait to get a replacement sensor and keep my fingers crossed that one will be ok!

 

[Eternal422]

The sensor seemed to be drifting off further yesterday and at times as much as 4 lower than BG (allowing for the lag between BG and ISF readings). Scanning it this morning first thing it came up with the sensor ended message. So it managed 8 days with only the first 4 being within accuracy tolerance. I’m just hoping this was a bad sensor and that my next ones will be ok. I called Abbott on Monday and they are sending out a replacement, so still waiting for that to arrive. I’ve not got this on repeat prescription yet so I’ll call the GP today and hurry that along. Even with these problems I really miss having it now and the ability to at least look at patterns!

I’ve also done removal which I had been a bit apprehensive about, but it peeled off fairly easily and the filament wasn’t bent at all so that wasn’t the issue.

The one thing I was a bit unsure about and something that wasn’t covered in the training, was how the mechanism worked. Initially I thought it was a needle on the sensor that stuck into you and that made me a bit fearful of how to remove it painlessly. It would have been great if they had explained that the applicator had a needle to deliver the flexible filament into your arm - I had to Google that to find that out!

 

[nonethewiser]

Thank you, that’s really encouraging. Looking back over the graphs tonight it seems to be roughly 2 to 2.5 lower, so I could live with that. I’ll need to give it longer over more sensors to see if it works for me, but so hoping that it will as this feels like a game changer.

Persevere my friend all will come good.

 

[Dyrck]

I'm type 2, so don't get the sensor on prescription. I buy my own and have a couple of weeks using it and then a few weeks without. I stopped my Metformin about a month ago so have been using a sensor continuously since then. All my sensors have been close to my finger prick tests but yesterday I started getting readings below 4, which struck me as unlikely, so checked against a finger prick test and the sensor is 2 or 3 lower. It's on day 12, so not too bad that it has failed. However this is the first one that has failed out of the 6 or so that I have used.

 

[Eternal422]

I'm type 2, so don't get the sensor on prescription. I buy my own and have a couple of weeks using it and then a few weeks without. I stopped my Metformin about a month ago so have been using a sensor continuously since then. All my sensors have been close to my finger prick tests but yesterday I started getting readings below 4, which struck me as unlikely, so checked against a finger prick test and the sensor is 2 or 3 lower. It's on day 12, so not too bad that it has failed. However this is the first one that has failed out of the 6 or so that I have used.

That’s what happened to mine, I was getting alerts during the night that it was 3.9 or less, but doing a finger prick test I was actually 5.6 or so. Thereafter the graphs showed similar patterns to before, but about 3 lower than it should be, until on day 7 it was reading pretty flat and was around 4 lower than it should have been reading. On day 8 it failed, showing Sensor expired.

Still waiting for a replacement from Abbott but also just got them on prescription which will be available on Tuesday. Can’t wait to get a sensor on again as knowing at least trends was so useful and somehow gave me more confidence, both in knowing that I’m controlling my BG and also not in danger of hypos.

It’s good to hear your failed sensor was out of 6 good ones, hoping that the reliability and quality improves with them.

 

[Dyrck]

That’s what happened to mine, I was getting alerts during the night that it was 3.9 or less, but doing a finger prick test I was actually 5.6 or so. Thereafter the graphs showed similar patterns to before, but about 3 lower than it should be, until on day 7 it was reading pretty flat and was around 4 lower than it should have been reading. On day 8 it failed, showing Sensor expired.

Still waiting for a replacement from Abbott but also just got them on prescription which will be available on Tuesday. Can’t wait to get a sensor on again as knowing at least trends was so useful and somehow gave me more confidence, both in knowing that I’m controlling my BG and also not in danger of hypos.

It’s good to hear your failed sensor was out of 6 good ones, hoping that the reliability and quality improves with them.

I replaced the sensor with the next one this morning. This showed 3.2 immediately and has stayed thereabouts ever since, so I suspect a bad batch . I don't have any more so will have to order a couple or hope for a replacement. It's an inconvenience but not a disaster for me.

 

[Eternal422]

I replaced the sensor with the next one this morning. This showed 3.2 immediately and has stayed thereabouts ever since, so I suspect a bad batch . I don't have any more so will have to order a couple or hope for a replacement. It's an inconvenience but not a disaster for me.

Not for me either, a nuisance, but at least I can go back to finger prick tests to make decisions on my insulin.

 

[Eternal422]

Well just got my replacement sensor from Abbott today after calling them last Monday, so it’s taken 5 or 6 working days (depending on whether you count the Monday as day 1 or not). Not bad and within their estimate of 5 to 7 working days so can’t complain. Also I should be able to pick up my prescribed supply of a couple of sensors later today so at least I’ll now have spares in case of any future failures!

Can’t wait to have the ability to scan and see my BG charts again!

 

[pawprint91]

Hi @Eternal422 - I got my first ever sensor yesterday and seem to be having similar problems - completely out of whack with the finger pricks, had to turn off alarms due to it telling me I was 3.0 when I was actually 4.8?? Then it was only 0.9 out before bed, but this morning back to 2 m/mol out. Did you take off your faulty sensor as soon as your new one was on the way? Hope you have more luck with this one!

 

[Eternal422]

Hi @pawprint91 , no I left my sensor on. The last day of getting readings it was 4 lower than finger prick tests then the day after it failed altogether (saying sensor expired on the app) which was when I took it off my arm.

Sounds like yours may be going the same way so probably worth giving Abbott a call if you haven’t done so already to get a replacement on the way. They just needed 3 examples of where it was reading lower.

Sorry to hear you are getting issues too. I’m just hoping that my replacement goes ok, but at least I have 2 spare from my prescription which I got yesterday so I should always have one even if I need to get a replacement ordered.

 

[void]

Hi,

I've had to turn off low alerts too. Currently reading 2.4 below fp readings :| this one has 10 days to go.
Has anyone experimented with placing the sensor on eg back of the calf, or on abdomen?