# Freestyle Libre - huge reading errors



## cairntoul (Oct 4, 2016)

Hi folks, just ordered a freestyle libre and inserted the first sensor yesterday.

After an hour I took the first reading: 16mmol. Confirmed with phone app and the libre meter. So I performed a stick test: 8mmol.

Performed multiple tests over the next two hours - similar results.

Later in the evening (give it time to settle I thought), the Libre reading was 8 the finger 5, so perhaps getting there?

This morning, Libre reading 9, finger reading 5.

I repeated this with multiple lifescan finger sticks from different packets and using 3 lifescan meters. All show the libre sensor having a massive error - up to 100%.

Now had I dose adjusted based on the Libre readings there would have been serious consequences.

So just wondered whether anyone had seen the same issue.

The data is there, the sensor scans, but the data is dangerously wrong. Dose adjusting on it would be catastrophic in this case.

Difficult to contact Abbott by phone as the number is not free, but potentially very expensive, for mobile users (another annoyance), which makes it very difficult for working people to get a hold of them.

Cheers


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## grovesy (Oct 4, 2016)

I am not a user but there are many on here who are! I am sure they will be along soon!


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## eggyg (Oct 4, 2016)

I'm now on my 8th sensor and apart from the first one where it showed I was constantly hypo for 24 hours, mine have been more or less spot on. Some say it could be dehydration, perhaps try drinking more water. If you haven't already, join the Abbott Freestyle Users Facebook page. Loads of advice. Hope you get it sorted, it's a very useful tool. Oh and by the way, welcome to the forum, we're a friendly lot, if maybe a bit nuts at times! Elaine


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## AndBreathe (Oct 4, 2016)

cairntoul said:


> Hi folks, just ordered a freestyle libre and inserted the first sensor yesterday.
> 
> After an hour I took the first reading: 16mmol. Confirmed with phone app and the libre meter. So I performed a stick test: 8mmol.
> 
> ...



Cairntoul - I am a part-time Libre user, and I am a real fan.  It is by no means perfect, but it has taught me a great deal about how my body functions, in the background.

One thing I will say is though is that some people (including me) find their sensors can be a bit,. erm,......... erratic during the first 24 hours, after application.  If you ring Abbott today and describe your sensor's activity, my guess would be they would want to know if it settles after another day.

Personally, having done lots of reading on people who are actually using the Libre, I now apply a sensor than eave it for 24-48 hours (usually 48 hours for me), before activating it.  Curiously enough, I have had far fewer "weird" sensors since doing this.

My theory is that some folks (including me) have quite a strong reaction to the application process - probably he puncturing of the skin), and recognising the foreign body under the skin (the Libre filament) it tries, with it's natural powers of healing, to reject the filament (like it would a splinter), by a fairly typical inflammation response - redness (although probably under the sensor), and very minor little swelling (flooding with body fluids) , before "getting used to" the sterile filament after c24 hours and settling down to give more reasonable readings.

Obviously, that isn't deep science, but it hangs together fr what happens to me.

In your shoes, I'd try to sit it out for another 24 hours or so, and see how it goes, then, if necessary, call Abbott to discuss it.  Their support services are very good.  

For future sensors, it could be worthwhile applying the new sensor and allowing it the c24 hours to settle and see how that works out for you.

Enjoy!


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## DeusXM (Oct 4, 2016)

cairntoul said:


> Hi folks, just ordered a freestyle libre and inserted the first sensor yesterday.
> 
> After an hour I took the first reading: 16mmol. Confirmed with phone app and the libre meter. So I performed a stick test: 8mmol.
> 
> ...




Isn't it a global freephone number? http://www.freestylelibre.co.uk/help-center.html

Some sensors are just genuinely 'wrong' - Abbott usually replace these FOC. 

For the record, I've been using a Libre constantly since December 2015 and haven't ever had an issue with inaccurate readings except for within the first 24 hours, where the sensor tends to read about 1.5mmol/l lower than a fingerstick.


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## Owen (Oct 4, 2016)

AndBreathe said:


> Cairntoul - I am a part-time Libre user, and I am a real fan.  It is by no means perfect, but it has taught me a great deal about how my body functions, in the background.
> 
> One thing I will say is though is that some people (including me) find their sensors can be a bit,. erm,......... erratic during the first 24 hours, after application.  If you ring Abbott today and describe your sensor's activity, my guess would be they would want to know if it settles after another day.
> 
> ...


I am watching this as I am considering using this system.

If you are applying the sensor and leaving it 24hrs, does this mean a gap in monitoring, or do have the old sensor still in operation?


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## Sally71 (Oct 4, 2016)

Owen said:


> I am watching this as I am considering using this system.
> 
> If you are applying the sensor and leaving it 24hrs, does this mean a gap in monitoring, or do have the old sensor still in operation?


Yes you can insert the new sensor while the old one is stil running, and just don't activate it straight away.  You can't actually have 2 sensors active at the same time, if you start the new one before the old one has finished then you can't read the old one any more.  But for the purposes of allowing the new sensor to "bed in", you don't want to start it straight away anyway, perfectly fine to have it just sitting there doing nothing!


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## Owen (Oct 4, 2016)

Sally71 said:


> Yes you can insert the new sensor while the old one is stil running, and just don't activate it straight away.  You can't actually have 2 sensors active at the same time, if you start the new one before the old one has finished then you can't read the old one any more.  But for the purposes of allowing the new sensor to "bed in", you don't want to start it straight away anyway, perfectly fine to have it just sitting there doing nothing!


Does this eat into the 14 days when not activated?


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## Diabeticliberty (Oct 4, 2016)

DeusXM said:


> Isn't it a global freephone number? http://www.freestylelibre.co.uk/help-center.html
> 
> Some sensors are just genuinely 'wrong' - Abbott usually replace these FOC.
> 
> For the record, I've been using a Libre constantly since December 2015 and haven't ever had an issue with inaccurate readings except for within the first 24 hours, where the sensor tends to read about 1.5mmol/l lower than a fingerstick.





The global freephone number is chargeable to mobile phones.

You are all aware that I have had similar issues to the ones report in the original post in this thread. When I have spoken to a number of other users face to face after an initial 'the system is perfect' conversation most users concede that they have had similar issues too. Don't get me wrong the system does have some advantages which is why I have elected to stick with it. Please do not fall into the 'Emperors new clothes' trap though. We all have a responsibility to potential users to report benefits and liabilities with equal measure


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## AndBreathe (Oct 4, 2016)

Owen said:


> Does this eat into the 14 days when not activated?



No.  I have done this for about 10 sensors now.


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## Sally71 (Oct 4, 2016)

Owen said:


> Does this eat into the 14 days when not activated?


No the 14 days goes from when you activate it.  You lose an hour of use while it's initialising, but that's all (and unfortunately there's no way of overlapping the old sensor to get round that problem, once you've initialised a new sensor the old one can't be read any more)


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## DeusXM (Oct 4, 2016)

> The global freephone number is chargeable to mobile phones.



Actually, that's entirely dependent on network. I believe it's free on O2 and Three, but worth double checking.

Abbott also have a UK freephone number as well - http://www.abbott.co.uk/contact.html - 0800 170 1177, which may also be able to help with any enquiries.


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## Diabeticliberty (Oct 4, 2016)

O2 charge me for ringing the number and I am on a business contract. I am going to ring them immediately and question why they insist on charging me and not you?


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## Diabeticliberty (Oct 4, 2016)

For the record I would once again hope to clarify my own position on this system. To the Libre Cheerleading Troupe I am certainly not anti or I would not still be using it every day and have done since buying it. I do feel however that there are a large number of users who just glibly accept what the system tells them no matter how bizarre the results appear. I am also opposed in principle to waxing lyrical about a system that has a number of flaws and not speaking out about them. I also still cannot comprehend how many of you just choose to ignore these flaws. Potential users who may just about be able to fund the system, should be fully aware of all of the facts before they go either investing in a system that may prove highly beneficial to their diabetic control or may prove to be a complete waste of money and nothing more than a fancy electronic paperweight


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## Owen (Oct 4, 2016)

Diabeticliberty said:


> For the record I would once again hope to clarify my own position on this system. To the Libre Cheerleading Troupe I am certainly not anti or I would not still be using it every day and have done since buying it. I do feel however that there are a large number of users who just glibly accept what the system tells them no matter how bizarre the results appear. I am also opposed in principle to waxing lyrical about a system that has a number of flaws and not speaking out about them. I also still cannot comprehend how many of you just choose to ignore these flaws. Potential users who may just about be able to fund the system, should be fully aware of all of the facts before they go either investing in a system that may prove highly beneficial to their diabetic control or may prove to be a complete waste of money and nothing more than a fancy electronic paperweight


I have just come off the phone to customer sales, support. Sadly this system is not ready to meet my requirements at this moment in time.
I will not reduce finger pricking due to being on the road so much.
Hopefully as accuracy improves and is recognised, I will have another look. The concept is great.


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## Sally71 (Oct 4, 2016)

Diabeticliberty said:


> For the record I would once again hope to clarify my own position on this system. To the Libre Cheerleading Troupe I am certainly not anti or I would not still be using it every day and have done since buying it. I do feel however that there are a large number of users who just glibly accept what the system tells them no matter how bizarre the results appear. I am also opposed in principle to waxing lyrical about a system that has a number of flaws and not speaking out about them. I also still cannot comprehend how many of you just choose to ignore these flaws. Potential users who may just about be able to fund the system, should be fully aware of all of the facts before they go either investing in a system that may prove highly beneficial to their diabetic control or may prove to be a complete waste of money and nothing more than a fancy electronic paperweight



Just to balance that - yes I'm one of the "cheerleaders" as you call them.  Yes, I love the system.  And that's because we have hardly had any problems at all with it.  I'm hardly going to report problems that aren't there, am I!  Whether we are exceptionally lucky, I don't know; I'm not trying to say that those of you who have had problems with the system are liars, just that we haven't had the same problems!
We had one sensor that failed, returned it and got a free replacement.  Another fell off because my daughter bashed her arm against a door, not a manufacturing fault so I didn't send that one back.  Apart from that they have all worked and stayed in with the help of some Tegaderm (although to be honest we just stick that on out of habit now, it might not be strictly necessary every time, but when you pay £50 a pop you want to make sure you don't lose the thing!) Regards accuracy, we still do finger pricks in order to work out boluses anyway, as far as I understand it no CGM system is as accurate as a finger prick because it isn't reading blood.  But if we read the Libre at the same time it's almost always within 2 mmol of the finger prick, which is close enough and within accepted tolerances.  We had one sensor that was a bit further off, but it still read high when she was high, low when she was low and in the middle when she was in the middle which is close enough for me.  I'm not particularly interested in analysing everything in detail and trying to predict the next HbA1c, but I do like having a rough idea of what goes on in between finger pricks, and I love the arrow that tells you whether the BG is rising or falling, that alone makes the system worth it for me.

As with anything, some people will love the system, some will hate it and some will be somewhere in the middle.  I guess it partly depends on how you want to use it, and also probably on a lot of luck!


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## cairntoul (Oct 4, 2016)

Folks, thanks for the input.

I was aware, anecdotally, of people having a 24hour bed in time. However this it's not mentioned anywhere in the manual (from what I can see), and there's a big difference in an error of 1,2 or even 3 mmol/L and one of 8. Even after 15 hours the error was huge (libre 9, finger 5). Then after 21 hours Libre 14, finger 8.

I did phone. The advisor did say that this could happen, but acknowledged that it was not explicit anywhere.

So someone sticks in a sensor, waits 1-24 hours then dose adjusts... Doesn't give a lot of confidence in the product.

I have graphed the data. The error (for this sensor anyway) is much less at much lower readings. This indicates it gives visibility of low blood sugars. However at mid to higher readings it is miles out. Looks fairly linear too.

So should we be doing finger sticks to check the sensor after application? Again no mention of this...

Cheers


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## Sally71 (Oct 4, 2016)

Yes, we do, not every time though. I would NEVER dose adjust based on the Libre alone; although actually, the way my daughter's pump works is that the only way to get her BG reading into it is by finger pricking.  So that's still 3 pricks a day; we scan the Libre at the same time as a check.  Must admit I've never had one as far out as yours (could still happen though!). So if you are hoping that the Libre will completely remove the need for finger pricks then you will probably be disappointed.  We have reduced the number of pricks we do by at least half though, another time the Libre is brilliant is when you are having one of those nasty hypos that takes ages to come up again; you can scan as many times as you like and as soon as the arrow starts pointing upwards you know you will be ok.  Much better than loads of finger pricks!


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## Northerner (Oct 4, 2016)

Sally71 said:


> So if you are hoping that the Libre will completely remove the need for finger pricks then you will probably be disappointed


I think Abbott are pretty much responsible for this belief, seeing their recent advertising - the need to check with fingerpricks is 'small print' i.e. something they don't expect most people to read, but they have to state somewhere for legal purposes - a major bugbear of mine, 'small print' should be banned! 

I'm considering trying a Libre myself. I have pretty good control, but I'm sure there are some circumstances I'd find surprising, and that I could take action over


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## Diabeticliberty (Oct 4, 2016)

Northerner said:


> I'm considering trying a Libre myself. I have pretty good control, but I'm sure there are some circumstances I'd find surprising, and that I could take action over



I would offer you the same advice as I would offer anybody else. Think very long and very hard about it. What they tell you over and above fingerprick testing is extremely limited and may not be worth over twelve hundred quid per year to you. In my in case the reduction in the need for fingerprick testing due to my occupation driving zillions of miles and lifestyle does make it worth it for me. This is obviously not the case for everybody and I urge any potential users to bear this in mind before buying. The discussion on here is good because you are such a fantastic moderator that you encourage everybody with a view to express it freely


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## cairntoul (Oct 4, 2016)

From what I can see they only recommend/instruct finger pricks if your blood glucose is changing rapidly - as indicated by the arrow when making the measure - due to the lag in interstitial vs. blood glucose measure. The actual slow moving data is represented by abbott as being accurate. If it is not then the use of the thing is becomes very limited - finger tests needed over the first 1-2 days to check accuracy then a test needed before adjusting any dose - shades of the glucowatch and certainly not what abbott portray it as.

For those people using it, do you have confidence in the numbers to an accuracy of 1-2 mmol?

Cheers


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## DeusXM (Oct 4, 2016)

Diabeticliberty said:


> O2 charge me for ringing the number and I am on a business contract. I am going to ring them immediately and question why they insist on charging me and not you?



As I said, I *believe* it's free but worth double checking. You might actually find that private contracts offer calls to 00800 numbers free, but biz contracts don't. I don't know, I'm not on O2, I'm just going on what I could see on Google and other discussion forums, which is why I said *check*.

The other options are of course to try the 0800 number I posted or (and here's a wild and dangerous idea) use a landline.


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## DeusXM (Oct 4, 2016)

> For those people using it, do you have confidence in the numbers to an accuracy of 1-2 mmol?



Absolutely. Generally the accuracy is within 0.5 mmol/l for me. As I said, I don't actually even bother with fingerstick testing anymore unless the Libre reading does not match up with my expectations.


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## Diabeticliberty (Oct 4, 2016)

DeusXM said:


> As I said, I *believe* it's free but worth double checking. You might actually find that private contracts offer calls to 00800 numbers free, but biz contracts don't. I don't know, I'm not on O2, I'm just going on what I could see on Google and other discussion forums, which is why I said *check*.
> 
> The other options are of course to try the 0800 number I posted or (and here's a wild and dangerous idea) use a landline.




I do like to live on the edge sometimes but using landlines is just a bit too much like naked parachuting. You can end up with someone else's equipment in your mouth. If you do wild and dangerous yourself I don't suppose you've tried this have you?


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## Robin (Oct 4, 2016)

I'm with Deus XM here, once I've done a few spot checks over the first few days of the sensor, if they accord with my meter, (and they usually do in the mid range) I don't bother to finger prick unless I'm driving ( you still have to finger prick by law every two hours). I find my Libre usually reads lower than my meter at the bottom end, and higher at top end ( over 10, say) but only by about 10% or so. I've just been using a sensor ( I use one for holidays, and sometimes in between times just to keep a closer eye on things) and I did have one reading that was surprisingly different, but I scanned again ten minutes later, and it was spot on with what my meter had said. You get used to the time lag.
I found mine invaluable for sorting out my nighttime readings. No 3am alarms needed, and I got far more useful data from just a few nights than I'd have got with months of waking  up and spot checking with a meter.


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## Northerner (Oct 4, 2016)

For me, I wouldn't be that interested in the numbers - I'm pretty comfortable with my awareness and general control. I probably wouldn't use it full time either as my diabetes and predictable lifestyle wouldn't warrant it, but I would be interested in seeing rise and fall, and extent, which might inform my insulin dosage timings. Whatever you think about them, and even if they are only reliable for 50% of people, they are a step forward and we've come a long way from boiling up your urine in a pan and sending it off to a lab to find out if you can have a second Rich Tea with your cocoa  I wouldn't adjust insulin dosage on the basis of any readings because I don't need to (due to 'weird' diabetes! )


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## Radders (Oct 4, 2016)

My initial idea was to get the starter pack, which is a reader and two sensors, to help in testing my basal rates and get some insight into how to adjust my pump during exercise. However subject to the same issues as described above in the first 16-24 hours of a new sensor, and the time lag, I have found it on the whole to be pretty accurate. I made a spreadsheet comparing finger prick and Libre readings and the average difference was less than 1.  I now do a finger prick before correcting or if the Libre reading is out of target range and before going out on my bike.  This has reduced the number of finger pricks drastically and given me some very useful insights into the mealtime spikes, the timing of boluses, and how protein affects my levels, to name but three. I am hooked.


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## cairntoul (Oct 4, 2016)

Well after 26 hours the latest is Libre 9, Finger 5. The scale factor is 0.6 (multiply Libre reading by 0.6 to get the finger reading). This increases to 0.75 as the libre reading drops towards 4 (gets more accurate).

So if it doesnt get better after another day then it'll be back on the phone.

Even if it does improve it is a big concern that this is not clearly publicised by Abbott in terms of accuracy/safety, never mind that the sensor is sold as a 14 day part and may need a 1/2/3 burn in - 3 days is 20% of its advertised lifetime(!)


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## AndBreathe (Oct 4, 2016)

cairntoul said:


> Well after 26 hours the latest is Libre 9, Finger 5. The scale factor is 0.6 (multiply Libre reading by 0.6 to get the finger reading). This increases to 0.75 as the libre reading drops towards 4 (gets more accurate).
> 
> So if it doesnt get better after another day then it'll be back on the phone.
> 
> Even if it does improve it is a big concern that this is not clearly publicised by Abbott in terms of accuracy/safety, never mind that the sensor is sold as a 14 day part and may need a 1/2/3 burn in - 3 days is 20% of its advertised lifetime(!)



Not everyone uses or needs to apply then wait, or apply then accept some wonky levels.  As I said earlier, I think some people's immunse system is just a bit frisky.  I'd count myself in there.  Once you've used a small number of sensors you will likely find it easier to ignore the sensor for a while before getting scan-tastic.


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## Robin (Oct 4, 2016)

If you are one of the people for whom it needs 24 hours to settle ( and I am) then inserting the sensor but not activating it for 24 hrs means you still get the full 14 days out of it.


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## everydayupsanddowns (Oct 5, 2016)

cairntoul said:


> Folks, thanks for the input.
> 
> I was aware, anecdotally, of people having a 24hour bed in time. However this it's not mentioned anywhere in the manual (from what I can see), and there's a big difference in an error of 1,2 or even 3 mmol/L and one of 8. Even after 15 hours the error was huge (libre 9, finger 5). Then after 21 hours Libre 14, finger 8.
> 
> I did phone. The advisor did say that this could happen, but acknowledged that it was not explicit anywhere.



It's really odd... I've seen presentatinos where Abbott have recorded different MARD (mean absolute relative difference) for the first 24 hours and felt sure it was mentioned in the manual, but like you I cannot find it.

I am another who has always had really useful information from Libre sensors over the past 2 or 3 years. I only use them occasionally for a bit of a 'reset', but I find that my BGs and range always significantly improve during the course of the 2 weeks from all the extra information. 

For me it boils down to taking decisions based on information, rather than guesswork - and being able to see what is going on 20-30 times a day rather than 6-8. But as has been suggested, this only really applies if you are getting a decent data-feed from the device. Like DeusXM I am far more used to differences of around 0.5mmol/L with only a few times in the day when it would be 1-2mmol/L out. Perhaps it has to do with biochemistry?

In your shoes I would certainly be contacting Abbott for a replacement as the sensor you are currently wearing seems to be performing outside of expected tolerances. It may settle in time (I had one that took 5 days before coming into line) but as you say... that is hardly ideal for a £50 sensor with a 14 day limit!

Would be interested to see what happens if you try another one - did you get the starter pack with 2 sensors in it?


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## cairntoul (Oct 5, 2016)

Hi folks, just short of 2 days and still out by a scale factor of roughly 0.6, so a massive error. This indicates that it is not sensor burn in. It also indicates a need to verify sensor performance with finger tests, which is a bit self defeating. I'll give it another day before contacting them which will allow me to gather more data.

I see that the glimp app seems to allow some form of calibration so may try that before ditching this sensor - nothing to lose now.


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## DeusXM (Oct 5, 2016)

cairntoul said:


> Hi folks, just short of 2 days and still out by a scale factor of roughly 0.6, so a massive error. This indicates that it is not sensor burn in. It also indicates a need to verify sensor performance with finger tests, which is a bit self defeating. I'll give it another day before contacting them which will allow me to gather more data.
> 
> I see that the glimp app seems to allow some form of calibration so may try that before ditching this sensor - nothing to lose now.




My maths isn't great - by scale factor, do you mean your readings are out by 0.6mmol/l, or something different? If it's 0.6 mmol/l, that's perfectly acceptable - you'd likely get this variance by using a different finger on one blood sugar meter.

Also, I know it's a nitpicking point, but Abbott have never said the Libre replaces finger tests, it's simply a way of more effectively gauging trends. There is a school of thought that runs it doesn't matter if the Libre is inaccurate as long as it is consistently inaccurate ie. as long as the margin of error is the same.

I really wouldn't bother giving it another day. Abbott tend to be very good at replacing duff sensors, so rather than spend another 24 hours getting frustrated at something that is obviously broken, I would just call Abbott from a landline, get a new one sent out and chalk this one up to bad luck. If you keep it in for too long, all you're going to do is give Abbott the arguement "well, you stuck with it for this long so evidently it wasn't that much of a problem." You're also, as I said, just making yourself frustrated, which won't have a positive impact on your blood sugar.

I would also add that Glimp is not your friend in this, I found that it could read anything from exactly what was on the 'official' reader to 10mmol/l higher. Glimp is a third-party app and not endorsed by Abbott and so any readings taken with it should be interpreted as dubious at best. If you're using your phone as a reader, stop and use the proper reader first.


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## cairntoul (Oct 5, 2016)

Hi there, the scale factor is what I need to multiply the libre reading by in order to get the finger reading.

So libre reading 10 = finger reading 6.

The scale reduces as the libre reading increases. It becomes more inaccurate.

Libre reading 16 = finger reading 8.

The 0.6 scale is the average.


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## sacol4940 (Oct 13, 2016)

I'm trialling a sensor at the moment..  Sometime the Libre readings match the finger prick test, and sometimes they're way out...  I only bolus based on the fingers prick test so I'm not too concerned.  I'm just using the Libre to look for trends etc...


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## Thomas Hill (May 3, 2018)

Sorry to dig up this old thread but google searching seems to bring this to the foreground mainly because Abbot Support staff are quoting people's experiences rather than their own documentation.

I'm on the 8th sensor and it's consistently reading 3-5mmol below my blood sugar after 14-hours.
So 2.2 after the first hour but my finger is reading: 6.5
6 hours later a reading of 3.8 was reporting: 8.7.
I appreciate there is a 15-minute delay, but previous readers have been 0.5-1mmol out previously.

Contacting Abbot support their first operative could not find my account, which is odd because they've sent me a replacement before.
The second operative I spoke to said that the device takes 24-hours to 'get used to the body'.

I actually think the '24 hours to settle down' myth has occurred because of forums and posts like this one.
In Europe the Libre has a 1-hour 'warm-up' period.
Once it's completed the device must be ready to use.
Otherwise it would need a '24 hour warn-up period'.
In the US, the period is '12-hours' and the device cannot be used in this window.

No where in the manual nor user-guide does it say it will be inaccurate for the first 24 hours.

In fact the Operating Manual provides the clinical trial results which says the opposite.
Stating the following: Page 47 - "Agreement on Day 1 against YSI Reference"
At 8-12hours 0.8% of readings were outside the +/-40% YSI comparison

Page 58 reports the Mean Absolute Relative Difference of Day 1 to be 13.8%  - Changing to 13.3% on Days 2-5.
Page 59 reports the Mean Absolute Relative Difference for Blood Glucose readings for Day 1 15%.

So the device shouldn't be any more than 15% out and the results show there is a a small percentage difference between the first day and later days.
My current device roughly -60% out!

Interestingly the documentation also says: 167 sensors produced glucose readings and are included in the analysis. There were 35 sensors that failed at insertion.  I wonder what classes a 'failure' in their study.

I'd also like people to consider how your body will acclimatize to the libre site.
If the bruising is affecting reading - it will take 3-4 days the the tissue to recover, in which case the device is inaccurate for much longer than 24-hours.  But this isn't documented.
If your body is reacting to the sterile filament like a splinter, it will get worse over 24-hours, not better.  Have you left a splinter in for more than 24hours?  Your body doesn't forget about it after 24hours, it will continue to fight against the foreign body.  But again that's not documented.

I believe the Abbot support staff are simply telling people to call again in 24-hours and accept the inaccuracy, even though Abbot's clinical trials document the acceptable ranges.

Anyway.... I'm going to call support again.  But don't want others to accept faulty devices!


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