# Libre 2 Sensor Accuracy



## Eternal422 (Aug 2, 2022)

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.


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## nonethewiser (Aug 2, 2022)

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.


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## trophywench (Aug 2, 2022)

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.


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## Eternal422 (Aug 2, 2022)

nonethewiser said:


> 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.


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## Bruce Stephens (Aug 2, 2022)

Eternal422 said:


> 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.)


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## Eternal422 (Aug 2, 2022)

trophywench said:


> 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!


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## Eternal422 (Aug 2, 2022)

Bruce Stephens said:


> 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.


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## Bruce Stephens (Aug 2, 2022)

Eternal422 said:


> 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.


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## Elizabethe (Aug 2, 2022)

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.


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## Eternal422 (Aug 3, 2022)

Elizabethe said:


> 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!


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## Eternal422 (Aug 4, 2022)

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!


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## nonethewiser (Aug 5, 2022)

Eternal422 said:


> 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.


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## Dyrck (Aug 6, 2022)

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.


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## Eternal422 (Aug 6, 2022)

Dyrck said:


> 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.


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## Dyrck (Aug 6, 2022)

Eternal422 said:


> 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.


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## Eternal422 (Aug 6, 2022)

Dyrck said:


> 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.


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## Eternal422 (Aug 9, 2022)

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!


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## pawprint91 (Aug 10, 2022)

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!


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## Eternal422 (Aug 10, 2022)

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.


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## void (Aug 24, 2022)

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?


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## void (Aug 24, 2022)

It seems the offset against finger prick testing isn't monotonic.

Right now the offset is -3.6 (earlier it was -2.4)


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## Eternal422 (Aug 24, 2022)

void said:


> 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?


That’s annoying.  I think I’ve seen someone on this forum mention placing one on their chest I think?  I’m sure someone will comment on what they’ve tried other than back of upper arms.


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## Eternal422 (Aug 24, 2022)

Great new on my replacement sensor from Abbott - it lasted the whole 14 days and stayed really close to BG throughout!  So pleased it worked and gave me some really useful data to help me adjust my insulin and get better control.

Now onto my third sensor and from the start it is pretty close to BG, and when BG is totally flat the sensor reads pretty much the same, so really happy with that!  I now feel confident to base dosing decisions on its readings.  Hoping this sensor lasts the course!


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## Proud to be erratic (Aug 24, 2022)

void said:


> 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?


When I wasn't needing to comply with DVLA remit I wore mine on my chest, which was fine. I was happy to just use FP for driving requirements.

With readings at 2.4 below FP, I'd ask Abbott for a replacement - that much differential below makes the sensor unfit for purpose in terms of hypo alarms. I've muddled along with sensors reading up to 3 above FP, because the high alarm isn't important to me and I can set the alarm a bit higher should I feel it necessary.


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## void (Sep 10, 2022)

I'm not finding the libre2 accurate at all. Regularly underreads by 2 to 5mmol.

I'm scratching my head to work out possible causes. it's been applied exactly as instructed.

next sensor goes on chest or stomach. it's accurate for about 8hrs on the arm. i probably sleep on it.


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## helli (Sep 10, 2022)

@void what are your readings like and when did you apply it?
Are you aware of the known limitations of Libre that have been mentioned many times on this forum.
For example,
- any readings above about 9 and below about 4 are totally unreliable. If you are seeing extreme variations when your levels are above 12, I am not surprised.
- some of us find the sensor can take a day or two to bed in. If you are seeing extreme variations within 48 hours of applying the sensor, your body may be reacting to the alien object in your arm 
- applying pressure to the sensor causes false lows. If you are seeing unreliable lows at night, this may be the reason.

Once we understand the limitations of the Libre system, many of us find it is a great tool. If these limitations are not understood, Libre feels like a complete waste.


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## void (Sep 10, 2022)

helli said:


> @void what are your readings like and when did you apply it?
> Are you aware of the known limitations of Libre that have been mentioned many times on this forum.
> For example,
> - any readings above about 9 and below about 4 are totally unreliable. If you are seeing extreme variations when your levels are above 12, I am not surprised.
> ...


This one was applied 9 days ago. With this one, the first 48hrs were the most in agreement, after that, here's the last few readings where I also took a fingerprick test, 1st column sensor, 2nd one the meter. I don't think my body reacts to the meter as there's no soreness or itching, and it's acceptably accurate at that time.


sensormeter8.215.03.65.95.78.94.07.89.113.64.17.35.710.54.47.44.99.33.47.9


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## void (Sep 10, 2022)

helli said:


> @void
> - any readings above about 9 and below about 4 are totally unreliable.


It wasn't mentioned in training. I am aware of the "lag" between fingerprick tests which test blood and are faster than the sensor that tests interstitial fluid. In training, a few minutes was mentioned, but I have seen some people report it can be a lot longer than that.


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## Proud to be erratic (Sep 11, 2022)

void said:


> This one was applied 9 days ago. With this one, the first 48hrs were the most in agreement, after that, here's the last few readings where I also took a fingerprick test, 1st column sensor, 2nd one the meter. I don't think my body reacts to the meter as there's no soreness or itching, and it's acceptably accurate at that time.
> 
> 
> sensormeter8.215.03.65.95.78.94.07.89.113.64.17.35.710.54.47.44.99.33.47.9


As I mentioned in an earlier response, once the sensor is below actual by c. 2.5 - and your readings clearly show this - it really isn't providing you with a reasonable degree of monitoring and certainly not giving you due warning when you are going low. With your sensor readings it's telling you that you are low when clearly not, so low alarms are useless and thus you can't anticipate forthcoming hypos. Also, your sensor to actual readings are very inconsistent; usually I would find my sensor to actual differentials were moderately constant, even if unacceptably big - when my BG was in steady state, ie a horizontal arrow. Even when I had vertical arrows, I can't recall differentials as great as a couple of your figures show; eg 8.2 to 15.0,  9.1 to 13.6 or 5.7 to 10.5.

The lag used to be declared as up to 15 mins for Libre 1, but claimed by Abbott as improved to 2.4 mins for Libre 2. I find it nearer to 5 mins. Knowing that delay exists, stops me from overreacting when Libre shows approaching 4 and I've already taken some response carbs. I can do this because I have my low alarm set for 5.6 and once I get that warning I monitor (ie flash scan) frequently and am ready to start snacking if it drops below 5. 

I'd struggle to determine much from your sensor readings and would have replaced the sensor before 9 days - seeking a replacement from Abbott. If my crystal ball was working well I might have anticipated that a replacement was going to be needed and fitted a new sensor very early - prepared to wear 2 sensors while the new one 'bedded in' for more than a day. I would only start (activate) the new sensor once I've finally given up on the errant sensor, which could sometimes mean 3 or even more days wearing 2 sensors.

But, for me, a sensor has become unfit for purpose if I have to finger prick every time I scanned (because I'd lost confidence in the scan reading - evidenced by figures like yours) or unfit because the sensor low alarm, in particular, wasn't giving me due warning of my true BG falling - before I actually became hypo.


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## void (Sep 11, 2022)

yeah I thought maybe it's just me, let it stablise. Out of the six sensors I've had, four have been returned due to this issue. That's why it's not gone back yet. I thought there was a limit on replacement. It's the weekend now, and Abbot won't be there. I'll try on Monday to get this one replaced.


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## nonethewiser (Sep 11, 2022)

void said:


> I'm not finding the libre2 accurate at all. Regularly underreads by 2 to 5mmol.
> 
> I'm scratching my head to work out possible causes. it's been applied exactly as instructed.
> 
> next sensor goes on chest or stomach. it's accurate for about 8hrs on the arm. i probably sleep on it.



Consultant once said to me that libre won't work for everyone for whatever reason no idea.

Those readings posted are way out & can see why your puzzled with results & cause, would be myself.  

Tbh find libre 2 very accurate compared to 1 & hardly had any issues with it, wish I could offer some advice mate.


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## Eternal422 (Sep 11, 2022)

Just an update on my experiences having read about other’s on this thread.  Only on my 4th sensor, but this one is doing well as the others have (apart from my very first sensor which read low then failed after 8 days and my 3rd sensor that read low on its last day).

I know that there are so many variables and people’s experiences will be different, but just in case it helps anyone I have a good example here which hopefully goes some way to explaining differences between BG and sensor readings.  This morning I got a sensor reading of 7.7 with rising fast trend arrow.  BG was 5.8, but then just 10 minutes later sensor read 6.  So just possibly I had a fast rising spike which subsided, meaning the sensor would be lagging behind as the BG fell (and hence reading higher than BG).  This may explain some of the differences between Libre and BG that we all experience.

It’s taken me a month of using Libre, but I’m now trusting it and not continually comparing against BG.  For me, doing this would make me continually doubt it and worry too much making it not worthwhile for me.  However, trusting the readings (unless they do not match how I feel) I have been going along ok and bolus according to the sensor readings without any issues.  Of course, my HbA1C will be the final judge of everything, I will get the result next week which will only include 1 month of Libre use but will be a starting point.

On a side note I have just started using the bolus calculation detailed in the “Think like a Pancreas” book, I.e. taking into account correction, trend and insulin on board.  So far so good, but wouldn’t it be nice if the Libre app had this built in which would save me having to enter figures on a spreadsheet on my phone to derive a bolus figure then back into the Libre app to record it?


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## Paul Goldie (Sep 11, 2022)

Just out of curiosity I have been searching the Freestyle Libre 2 FAQs and web pages to see if they advise what would be classed as an acceptable tolerance between sensor and meter readings but can't see anything. does anyone know if there is one? Thanks.


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## Eternal422 (Sep 11, 2022)

Paul Goldie said:


> Just out of curiosity I have been searching the Freestyle Libre 2 FAQs and web pages to see if they advise what would be classed as an acceptable tolerance between sensor and meter readings but can't see anything. does anyone know if there is one? Thanks.


I have seen a figure on the Abbott website of 11.4% MARD (Mean Average Relative Difference) against finger prick tests.  So I gather this means that the Libre reading could be +/- 11.4% of the finger prick reading.  https://freestylediabetes.co.uk/freestyle-thinking/post/accuracy


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## void (Sep 11, 2022)

nonethewiser said:


> Consultant once said to me that libre won't work for everyone for whatever reason no idea.
> 
> Those readings posted are way out & can see why your puzzled with results & cause, would be myself.
> 
> Tbh find libre 2 very accurate compared to 1 & hardly had any issues with it, wish I could offer some advice mate.


The one I (was) wearing (up till waking up this morning) stopped with "the sensor has ended" I think this one had 8 days to go. This mornings real glucose was 4.8.


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## void (Sep 11, 2022)

newly fitted sensor seems to be doing well, touch wood. Within 0.1-0.5 mmol. It's on the top of my chest rather than an upper arm. Interested to see if it remains accurate or starts failing in the next 60hrs or so


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## nonethewiser (Sep 12, 2022)

void said:


> newly fitted sensor seems to be doing well, touch wood. Within 0.1-0.5 mmol. It's on the top of my chest rather than an upper arm. Interested to see if it remains accurate or starts failing in the next 60hrs or so



Good stuff, I've worn sensor on chest with great results, hope it continues for you.


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## harbottle (Sep 12, 2022)

I've used about 5 of these sensors, and have noticed with all of them:

- Initially (About half a day) they are always very high, but slowly drop down. (Starting by reading 8/9 when finger test reads 5/6)
- they are fairly close to finger prick tests (Using a contour Next)  for around 7-10 days (Usually within 1, generally less.)
- after that they start to drift away quite a lot (Sensor reading > 7 when FP reads around 5.)

I tend to ignore the 'value'  most of the time and just look at the trends and how different food affects me.

Placement seems important, as moving my arm and doing any sort of activity seems to cause major disruption with the readings.


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## helli (Sep 12, 2022)

harbottle said:


> - Initially (About half a day) they are always very high, but slowly drop down. (Starting by reading 8/9 when finger test reads 5/6)


Have you tried applying them half a day before activating? It is common for our bodies to take some time getting used to the alien object in our arm which affected the readings.


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## void (Sep 13, 2022)

harbottle said:


> Placement seems important, as moving my arm and doing any sort of activity seems to cause major disruption with the readings.


Maybe flex affects perfusion, maybe that's it.


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## rebrascora (Sep 14, 2022)

harbottle said:


> Placement seems important, as moving my arm and doing any sort of activity seems to cause major disruption with the readings.


That is surprising as I do quite a bit of physical work with my arms cutting hedges manually, grooming horses, mucking out etc and don't have any problem with my Libre in that respect.


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## void (Sep 14, 2022)

nonethewiser said:


> Good stuff, I've worn sensor on chest with great results, hope it continues for you.


Same great results, now four days in. Largest deviations have been +/- 1.0 mmol. Given that I can get that difference with different fingers on the same hand, i'd say this one is working very well indeed (touch wood).


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## void (Sep 15, 2022)

it's been very useful in identifying overnight lows, then I gradually adjust basal. If I can get the sensors to work accurately consecutively then it'll be a real game-changer.


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## helli (Sep 15, 2022)

void said:


> it's been very useful in identifying overnight lows


Take care with reported overnight lows. These may be compression lows - false lows caused by pressure being applied to the sensor when you lie on it.


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## void (Sep 15, 2022)

helli said:


> Take care with reported overnight lows. These may be compression lows - false lows caused by pressure being applied to the sensor when you lie on it.


thanks, but thats been accounted for (now), because now it's on my chest and not my arm, and I don't skeep sleep on my chest. Almost always on the side or on my back.


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## nonethewiser (Sep 16, 2022)

void said:


> it's been very useful in identifying overnight lows, then I gradually adjust basal. If I can get the sensors to work accurately consecutively then it'll be a real game-changer.



Must admit it is so beneficial overnight for adjusting basal rates, like my sleep & hated waking to test bg, so libre fits beautifully  to fulfill that need.


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## void (Sep 18, 2022)

this one has retained its accuracy very well so far. it has eight more days left in it according to the app


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## Robert459 (Sep 19, 2022)

Eternal422 said:


> On a side note I have just started using the bolus calculation detailed in the “Think like a Pancreas” book, I.e. taking into account correction, trend and insulin on board. So far so good, but wouldn’t it be nice if the Libre app had this built in


The Libre reader has this ability after a finger prick as long as you use it to enter insulin and carbs.  It is in the "professional" section of settings but you could google the code


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## void (Sep 19, 2022)

Robert459 said:


> The Libre reader has this ability after a finger prick as long as you use it to enter insulin and carbs.  It is in the "professional" section of settings but you could google the code


Do you mean the android app or the dedicated reader device? I can't find this setting in the android app


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## grovesy (Sep 19, 2022)

The dedicated reader has a port to take Freestyle Optium tests strips, for glucose, and separate ones for ketones.


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## Robert459 (Sep 19, 2022)

The dedicated reader device, you would use it to test the finger prick blood.  Not sure an android phone can read a test strip, iPhone can't


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## void (Sep 19, 2022)

Robert459 said:


> The dedicated reader device, you would use it to test the finger prick blood.  Not sure an android phone can read a test strip, iPhone can't


ah sorry it wasn't clear to me that it'd need to directly read the blood (rather than entering or reading data in via some other source)


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## Bruce Stephens (Sep 19, 2022)

void said:


> ah sorry it wasn't clear to me that it'd need to directly read the blood (rather than entering or reading data in via some other source)


Yes, that's what the Libre reader requires. Which is annoying, but I presume that was the requirement from the FDA (or some other body).

(There exist other bolus calculators where you can enter readings. I used one for a bit but just gave up after a while since it just wasn't useful enough. Now I just calculate in my head, with the occasional help of a calculator.)


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## Robert459 (Sep 19, 2022)

The 'Reader' actually is a pretty intelligent device.  You can set different ratios for different times of day, but you have to use it for your main input device.  I guess most 'youngsters' prefer to use a smartphone


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## Bruce Stephens (Sep 19, 2022)

Robert459 said:


> The 'Reader' actually is a pretty intelligent device.  You can set different ratios for different times of day, but you have to use it for your main input device.  I guess most 'youngsters' prefer to use a smartphone


I think the readers are being discontinued so if you're newly prescribed Libre you won't have an option. (The non-smartphone option seems to be an Android thing that's basically a smartphone with just the LibreLink app.)

In an alternative timeline I could imagine connected pens (like the Novopen Echo Plus) came out 5 or 10 years ago, and then when Libre came out it would be natural for the Reader to be able to just scan those. In that case the Readers would be rather more natural to use. (Compared to smartphones their screens suck as input devices.)


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## helli (Sep 19, 2022)

Robert459 said:


> The dedicated reader device, you would use it to test the finger prick blood.  Not sure an android phone can read a test strip, iPhone can't


There is an attachment for an iPhone which allows it to read test strips.


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## Robert459 (Sep 20, 2022)

helli said:


> There is an attachment for an iPhone which allows it to read test strips.


Cool, will look into it


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## Bruce Stephens (Sep 20, 2022)

Robert459 said:


> Cool, will look into it


I think a few members have used AgaMatrix Jazz meters. (Not sure about the Jazz Wireless 2 (which is the Bluetooth variant) but I assume it's basically the same, but where you can use a phone app to read the results.)

(I can't see any sign that their app has a bolus calculator, but maybe it (or one of their partners) does.)


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