Posted by on Sunday, 26 October 2014

Abbott Freestyle Libre results vs BG meter - Review part 2

Last day of 2nd sensor. Complete with crazy-flat overnight graph.
In this update to my initial review of the Abbott Freestyle Libre I wanted to share my experience of what it was like to use and also to provide the promised comparison with results from my regular fingerstick meter (the Contour Next Link USB). If you have been living in a cave and have no idea what I'm on about you can get an introduction to the Libre here.

It is probably worth pointing out at the outset that the Libre WILL NOT give you identical readings to your BG meter all the time. It just won't. They are not even measuring the same things. If that's what you want the Libre to do, you can pretty much stop looking, because it's not going to happen - not with the Libre and not with *any* technology that measures glucose in interstitial fluid and then converts that into an estimate of plasma glucose values (so all current CGM options). More on that later. But first - what is the Abbott Freestyle Libre like to use?

Do the sensors come unstuck?
I found the Libre to be extremely comfortable and unobtrusive to wear and both sensors stayed firmly stuck for the full 14 days. I was almost never aware of the sensor being there, with the exception of one or two times when I leant on it or absent mindedly scratched near it (having forgotten it was there). I did deliberately try to remember it when towelling off after showering to make sure I didn't accidentally dislodge it, but apart from that I barely gave it a second thought. There was very little in the way of itchiness for me and at the end of 14 days the sensor removed to reveal, well... nothing very much. Insertion of the second sensor was as painless as the first. I have seen some comment online where people have found that sensors came loose after just a few days, but that certainly didn't happen to me. With infusion sets I have found that the adhesive seems to need 12-24 hours to get up to full strength. I suspect it is the same for the Libre sensors. If it gets loosened early on you may need to over-tape it with Opsite Flexifix, Tegaderm or something similar. There's not a lot of 'edge' on the sensors and I can see the possibility of the sensor getting 'levered off' if knocked in just slightly the wrong direction. placeholderplaceholder

I wonder what my levels are now?
I think this picture sums up my experience of living with the Libre for 28 days. Since I started attempting to *actively* manage my blood glucose levels four or five years ago I spend quite a lot of time wondering what is going on between my BG checks. I have never really known how often this happened until now - but the Libre released me from any monitoring constraints. So there you go. An average (average!) of 31 checks a day. Something like once every 30 minutes during waking hours. I had expected that my frequency would drop off after the initial excitement, but I remained fairly consistent through the full life of the sensors - checking more frequently when levels were changing more rapidly and leaving hours between checks at times in the day where things are generally more stable. The inconvenience and discomfort of 'traditional' punctured-finger-and-strip-fiddling monitoring means I would never check this often via a BG meter, but for 28 days whenever I wondered what my levels were, I found out. It is easy to underestimate how much of a transformation this is. Any time. Every time. All the time. I could know what my levels were *and* what they had been over the last 8 hours. There was no longer any reason not to look. No 'avoiding' the numbers (whatever they might be!) in between my 'normal' testing routine. Rather than feeling swamped and judged by data I felt completely liberated.

Basal test every day
In my previous post I mentioned how amazing it was to suddenly be able to see what had happened overnight every morning. Overnight basal tests are - as everyone who has undertaken them will know - a real chore. Waking every couple of hours to check blood glucose via fingerstick is a very effective management technique - but it's no fun. But look at what happened when I had 28 consecutive basal tests - the result is at the very top of this post. I couldn't help but tinker with my overnight basal profile gradually moving it from a bit wobbly, to ridiculously level (at least for a short while!). Seeing the patterns every day meant it was easy to spot the general trends and ignore the one-offs. And I made alterations to the 'shape' of my overnight pattern that I would *not* have made without those data.

New technique
After I had been living with the Libre for around 7 days I noticed that I had added a whole new technique to my management armoury. The preventative TBR (temporary basal rate). I've regularly used them since I started with Artoo to cover activity and other things, but this was slightly different. Because of the constant availability of data and the trend arrow that accompanies each check, I found myself setting short sharp TBRs - perhaps 50% for 30 minutes or an hour - to head off an impending dip in glucose levels. I was slightly surprised to realise that the 'level' trend arrow on the Libre doesn't actually mean level as such. It just means not rising/falling fast or very fast. In the first week on sensors I ignored a lowish level because of the 'flat' arrow only to dip below 4.0mmol/L an hour or so later. By using preventative TBRs for flat or more accurately reading-flat-but-slightly-falling readings that were just 'a bit near the edge' I managed to avoid several low level hypos and without bouncing up into double figures. Similarly, micro-boluses of small fractions of units when levels were high-ish (but not yet out of range) allowed me to be bolder in preventing BG drift. WIN!

Data analysis
I really like the simple, clear overview screens on the Libre. They might be a bit simplistic for some, but by dividing the day into four chunks and averaging 7, 14, 30 and 90 days of results in those sections I found it very easy to spot patterns and filter out the ebb and flow of 'diabetes randomness'. I particularly liked the 'Daily Patterns' graph which only appears after 5 days of results are stored and offers an average of daily results along with a 90th and 10th centile shaded area (it's a simplified version of the Ambulatory Glucose Profile graph - see image). It becomes very easy to see which periods in the day are providing the most challenges. You get a similar view (but with many more options, and helpful traffic lights) when you connect the Libre to your PC (or Mac - hooorah!). The Libre software niftily allows you to create smart PDF reports recording all sorts of averages, graphs, low glucose events and mealtime patterns which can really help to understand what has been going on. Additionally any mealtime notes and/or carbs and other details that you may have chosen to record on the libre are transferred for review too. If you have a particular penchant for number crunching you can also download up to 90 days results and details as a 'tab separated' txt file ideal for import into your spreadsheet package of choice. Look for the 'File' menu at the top of the screen, and choose 'Export Data'.

The end result of my 28 days? I had some of my BEST results all year. Lower post-meal spikes, fewer lows, fewer highs. Not bad Abbott! Thank you very much Freestyle Libre.

Ready to insert second Libre sensor
Libre results vs BG meter
Well... this is all very well you say. But if the results the Libre is providing are complete garbage, then it doesn't matter a hoot how nifty the downloaded PDF reports might be.

So how reliable were the results?

It's a good question. And not necessarily an easy one.

As I suggested earlier the Libre is reading glucose levels in interstitial fluid (via factory calibrated sensors) and then interpreting those through an algorithm to present values intended to reflect plasma glucose levels. That's a whole lot of steps in between what the Libre reads and the results you receive. And much as I realise a lot of work will have gone into ensuring that those results will be mostly OK for most people most of the time - clearly it is likely or at least possible that some variation will occur. Not least because the glucose values in interstitial fluid will 'lag' behind blood glucose values (typically 10-15 minutes, though the Libre aims for 5). Things are complicated further by the +/-20% variability which is allowed between BG fingerstick strips (though again these days meters tend to perform more like +/-5% or 10% most of the time).

What matters more to me is not whether results are identical all the time - it is more whether the results I get are useful. Whether any variation is modest enough that the readings, trends and analysis help me manage my diabetes better.

In order to understand what I was getting from the Libre I tested both sensors against my standard BG fingerstick testing routine. This is usually between 6 and 10 fingerstick tests a day, including premeal and post-meal tests as well as those around driving, exercise and activity. Whenever I took a BG fingerstick test on my 'normal' meter (the Contour Next Link USB that works with my pump) I cross-checked with the Libre. At the end of each sensor I then downloaded all the data and compared it on a spreadsheet to see what (if any) differences there had been. I do not for a minute pretend that this is a scrupulously scientific test - or that the results here might apply to anyone else. I took these comparisons purely for my own interest, and share them here in case others find them useful.

Here's a summary table from the first sensor - there were 94 pairs of results (BG meter vs Libre) over the 14 days:

Sensor 1
BG meterLibreAvg +/- %
(against BG meter reading)
Avg +/- mmol/L
(against BG meter reading)
Distribution of readings
Number of readings where Libre higher1819%
Number of readings where Libre lower7075%
Number of readings equal66%
Number of readings within 0.5mmol/L4346%

I don't know about you - but that looks pretty darned good to me. Yes, in amongst that there were some readings which were substantially different. A handful of times around 40% different from the BG meter - to put that into context one was a 4.4mmol/L that read as a 6.1mmol/L - one needs watching the other doesn't. There were also results where the Libre read hypo, but my BG meter confirmed I was in the 5's.

But the vast majority of the data feed is well within usable limits for me. The SD line gives a useful estimate of the range of most of the results. So from an average of 0.7mmol/L difference the most of the results were somewhere between 0.1 and 1.3mmol/L out.

You will notice that in most cases (but not always) the Libre was reading lower than my BG meter - with the result that overall the average of all results for the Libre comes out at 0.4mmol/L lower than my Contour Next Link, but with a slightly wider range (SD of 3.0 vs 2.8). Amazingly though, almost half the time the Libre was reading within 0.5mmol/L of my BG meter - and don't forget that at least some of the differences in readings could be down to the 5-10 minute 'lag' between BGs and interstitial glucose - especially if BGs were moving fairly rapidly at the time.

What I think this means for me in practical terms is that if I was running off results from the Libre more or less full time, with only a few cross-checked results where BG was moving rapidly or if things 'didn't feel right' I would most likely run a little higher most of the time. This would probably do wonders for my avoidance of hypos, but I suppose it may also have a small knock-on effect on my HbA1c.


Isn't there always a 'but'?!

Things get a little more interesting when I switched to Sensor 2. As soon as that sensor started reading the graph 'jumped' down the screen. If the first sensor had tended to read a little lower, this sensor was taking that to new levels. Now Abbott do suggest that the Libre sensors may not read quite so accurately on day 1, but that days 2-14 should be relatively steady. Even on the second day though readings on the Libre were consistently 2mmol/L or more lower. And since there is no calibration option there was absolutely nothing I could do about it.

Here are the results for the first 5 days of that sensor:

Sensor 2 - days 1-5
BG meterLibreAvg +/- %
(against BG meter reading)
Avg +/- mmol/L
(against BG meter reading)
Distribution of readings
Number of readings where Libre higher12%
Number of readings where Libre lower4398%
Number of readings equal00%
Number of readings 1.5mmol/L or more out2659%

You can see the difference in performance for yourself - over twice as far out. Suddenly almost 60% of the time the readings were 1.5mmol/l or more different and almost always lower. I had a few overnight traces that looked as it I'd been on the verge of a hypoglycaemic coma all night - when in reality I'd just been bobbling along in the low 5's (I know because I panicked and checked). On several occasions the Libre just reported 'LO' - with (allegedly) a level too low for it to record.

After several days of 'waiting to see' I contacted the lovely folks at the Abbott helpline who ran through a few checks to make sure I had the sensor in the right place and generally could tell my Libre from my elbow. I had been given a handful of Freestyle Optium Neo strips with my pack of goodies and the helpline person suggested I tried cross-checking against the Libre's inbuilt BG meter rather than some other technology (interestingly these strips also read a smidge lower than my ususal meter). As it turns out the reading on that occasion was pretty close (typical!) so I left it at that and wished I'd called them earlier.

The plot thickens
A couple of days later I had a call from Fiona who I'd met at the Libre pre-launch meeting called to say that a software glitch had been discovered (and fixed) in some of the very early sensors which was causing some interruptions in data and other concerns. I related the issues I'd been having with the second sensor and while they didn't seem to exactly fit with the software glitch described, Fiona offered to replace the second sensor.

In the meantime, and certainly into the second week, the second sensor seemed to be settling down considerably and behaving much more like the first. Here are the results averaged from days 6 to 14:

Sensor 2 - days 6 to 14
BG meterLibreAvg +/- %
(against BG meter reading)
Avg +/- mmol/L
(against BG meter reading)
Distribution of readings
Number of readings where Libre higher1527%
Number of readings where Libre lower3869%
Number of readings equal24%
Number of readings within 0.5mmol/L2138%

Not exactly back to the performance of the first sensor, but pretty darned close. Of course it did take those 5 days to settle. And if I'd been stumping up hard-earned cash for that sensor I suspect I might have been quite miffed that data from 36% of the life of the sensor was fairly useless to me.

I would have expected that a relatively consistent error would have still yielded useful 'trend' data - but in reality I found it very difficult to detach myself from the uneasy feeling that 'red' (hypo) results gave. However much I knew, or suspected, that my *actual* BG level was 1.5-2.5 points higher it was impossible for me to use the information in the same way when the margin of error was that great.

So in the end I am left with one spare sensor yet to use (which I plan to put into action around Christmas time) and just a very slight sense of unease as to what future sensor(s) might bring. When it worked at the 10% MARD that Abbott promise in the marketing literature I found it an incredibly powerful tool. If it were available on prescription and performed consistently like that I would be banging the table and asking to swap my (fairly generous) fingerstick allowance for Libre sensors - topping up with as many strips as I needed on top of that out of my own pocket.


If other sensors only perform to the accuracy of the first 5 days of Sensor 2 then it's a whole different ball game. I wonder if Abbott may come to regret their decision to go for factory calibration. From a user's perspective I have already seen several posts from people who would find it very useful to have a 'manual override' setting where you could offset Libre readings which are consistently out to bring them more in line with our own fingersticks.

All in all I love the Libre and I am really hoping that future sensors live up to overall positive experience I have had so far.

Now that the online shop has opened I'd be interested to hear your experiences if you have used the Libre yourself.

Final verdict: 4/5.

Update: Freestyle Libre now licensed for use in under-18s


  1. Your experience over the first five days with the second sensor is what I have experience with all three sensors I have tried so far. Abbott sent me a replacement for my first sensor which decided to end itself after one day. They told me to swap my second sensor with the replacement they had sent me due to continual 'LO' scans when BG readings were in the 5 -6 range. I'm on the third day of my third sensor - first day was a disaster, second day was still over minus 2.0 mmol out. Third day - well it's getting a little closer but I am having to let my glucose levels run higher than I would like to stop the sensor reading 'LO'.

  2. Hi Mike,
    I'm in the first 24 hours of my first sensor, and so far the readings have been all over the place as compared to my regular BG reader. I'll give it some time to settle. By the way you had me in tears with your "tell my Libre from my elbow" remark :-)
    I have a different question: I just noticed a spot on my conveniently white sweater, just over the place where the sensor is. It looks like wound fluid, not quite blood. Have you noticed any "seepage" in use of the sensors?

  3. Hi Marieke
    Thanks for reading :)

    I did see some pics on Twitter of people who had some blood/etc below the sensor when they removed it so I guess it's possible - but no... You can see from the pic towards the top that shows the site of the first sensor after all 14 days. The second was much the same - and much less 'wound-y' (real word) than infusion sites seem to get after just 3 days.

    If you have concerns I you could always call the helpline peeps - they are very lovely. Other than that - unless it starts hurting I would probably just keep an eye on it.

    Hope your sensor settles soon.

  4. Hello Mike,
    It is very exciting to read all of your comments and a lot of reviews about this device. I’ve been following many of them out there since the first time I heard the news about Libre receiving the CE Mark release. I live in Puerto Rico so we are part of the United States. That mean we won’t be able to get our hands at the Libre any soon and God knows how long we would have to wait until the FDA give its approval on this side of the planet. Until then, we would have to keep reading about your experiences with it while our eyes get drowned in tears of hope and joy.
    In the meantime, I have a few questions that I will really appreciate if you can help me find the answers for them.
    1. Can anyone tell me if the Libre has an option to select the measurement units between: mmol/l or mg/dl? As our current measurement unit is mg/dl this is a most for us so we don’t have to be converting mmol/l to mg/dl by multiplying the results by 18.
    2. Does anybody know what the youngest age to use the device is? It seems like it has to be like +18 years in order to use it but I’m not sure.
    3. If so, has Abbott issued a statement about this restriction?
    4. Can I just buy it without a medical prescription by sending money to a friend or relative leaving in Europe? I'm dying to test this device.
    Thanks all for your valuable information. Please keep up the good job!!!

  5. Thanks for you reply Mike. I'm not too worried and it's not hurting. I left a message at the help line to be called back, I bet they are pretty swamped since the introduction in the Netherlands.
    My values seem to be getting more aligned with the regular BG measurements now, so I hope it's just a 24 hour settling time for this sensor.
    I was surprised to find that the software won't let me download the data from the reader, which means I can make reports and save those, but I won't have the actual data from more than 90 days back. I wonder what the rationale is behind that.

  6. Hi Marieke - you should be able to download and keep up to 90days of data. I'm not sure it was very clear that was what the option was for - I seem to remember it was called 'Save as text' or something similar, possibly under the 'File' menu. You then get a tab-separated file with everything in (as far as I can make out) which you can open and manipulate with your preferred spreadsheet software.

  7. Hi Miguel

    The device is available as mg/dl in countries that use that standard I believe. But there is no option to switch on the device itself as far as I know (though I've not tried to be honest).

    At launch the device was licensed for use by over-18s only and with sensors on the back of the arm only. That was because that was the research data that Abbott had. Of course now it is out 'in the wild' I have seen reports of people trying sensors elsewhere, and buying it for use in under 18s but those are 'off label' uses so I'm not sure what the situation is with Abbott if sensors fail problems are encountered etc.

    I do know that Abbott are actively pursuing approval for use in under 18s and I woukd e very surprised if they are not working hard with the FDA for access to the U.S. market.

    If I hear any updates as far as that goes I will post an update.

  8. Miguel, another happy freestyle libre user trying to answer 2 of your questions below:
    1. changing the measurement units between mmol/l andmg/dl does not seem to be possible.
    4. So far i've found you can only buy the device through the official webshops located on www.freestylelibre(.nl/ etc...). I've purchased the starter kit from the UK webshop and shipped it to Germany using borderlinx. No medical prescription was required to puchase it.

  9. Mike, Very interesting to hear your continuing experience and all that data analysis - wow, I'll go through that again later!
    I have had an interesting experience with my first sensor. Worked well for the first three days, then walked into work for the first time with the sensor and 'beep' went the security gates. I work in a library, it was not the usual 'beep beep beep' that is emitted when someone tries to escape with a free DVD. Just a quiet 'beep' - thought nothing of it, went to check reading an hour later and the meter could not detect the sensor. A nice chap at Abbott talked me through some checks on the meter, these indicated no problem. Almost as an after thought he asked me if I had had any problems with security gates. Oh yes, now that you mention it......He said they'd had a similar problem with one other person (?) and were querying whether it was a problem with a particular batch. In the mean time I am using the back door at work and will try coming in the usual way on day 13 of this sensor! Any similar experiences out there?

    1. I was that other person they had had a report from about a problem with security gates!
      I 'nuked' my first sensor at work by going through the security gates into our library's lending centre. I now open the emergency door at the side to get through, going round the gates.
      The gates did the same as they did with you Ceri, blinked red once, not the usual three times when someone goes through with an un-checked item.
      I phoned Abbott, reported the problem, but they didn't want the sensor returned, for them it seemd logical that an RFID system would 'nuke' the sensor.
      I have tried going through the gate again wearing a sensor that had only 1 hour of life left and checking how close to the gate I have to be to set it off (i.e. how far away from the gate I have to be to NOT set it off!). Our gates appear to have a small gap (no overlap in the middle) and I can walk through if I keep the senor in the middle.
      Since I've started to wear the sensor just below my collar bone, this is no problem.
      ... But I still use the side door: My German health insurance company has still to decide to cover the costs and so I'm paying 60 Euros every two weeks!

  10. Thanks Ceri! Not heard of anything like your security gate issue - I wonder if it's some sort of Near Field Communication overload? If you don't mind I'd be really interested to hear if you manage to repeat the event!

  11. This is worth listening to

    Prof Tim Noakes on diet for diabetics

  12. Hi. I had the Libre mentioned to me (not as a recommendation) by my consultant at my 6 monthly review today. Since returning home I have read through a number of comments such as this excellent blog.
    Re the "security gate" matter reported above - would there be any issues with airport security perhaps?

  13. Hi Anon, Since this blog was posted I have picked up (via a Facebook group) that other people seem to get problems with library security systems in the UK - it seems to be something particular to libraries from what I can make out. Abbott said in the presentation I attended that flights/flight security should not be a problem, and there doesn't seem to be an issue with the doorway security in shops or supermarkets.

    If I were wearing a sensor I would personally try to avoid going in and out of a UK library, if I remembered! :)

    Hope that helps

  14. Thanks to @4gra on Twitter for the nudge about data export. I have updated the post above to clarify where the 'Export Data' option lives in case people struggle to find it.

  15. Does anyone have any information on when a new customer can order the Libre system? Thanks!

  16. Only rumours, and might very by territory. End of March seems possible though.

  17. Yesterday I ordered my new libre.

  18. 1st reading was spot on

    then over the next hour readings dropped so it was 3mmol out
    putting me at dangerous 3.3mmol reading :¬(

    abbot said ignore the 1st 24 hours readings

    I said why do you log these readings if they are invalid also does this not defeat the purpose if we have to keep using blood test strips in case the device is reading bad

    The didn't seem to worry about this at all (I do)

    Seems this device is not fit for purpose and is borderline dangerous
    and not health care professional would trust these values in anyway

    :¬( sux I so wanted this to work
    born to early dam wish I was in 3015

    1. I am very much with you on this. Taking into account the lag between this and my BG meter the Libre is always anything between 0.6mmol to 3mmol under reporting - which means I am always having to cross check with my BG meter, so defeats the purpose of this device. I am onto my second sensor with Abbott replacing the first sensor. I am still miffed at the under reporting. With the new ISO standards in meter readings I wonder how long Abbott last - from memory Baxter were run out of the industry due to wayward reporting and suffered massive losses.

  19. Hi Anon

    I think you are being pretty hard on the technology there. Things are improving so much in recent years, but FGM and CGM are reading interstitial fluid, not blood so there are likely to be discrepancies here and there. After all it's not as if BG meters themselves are much more than a guide (ISO for +/- 20% of lab results 95% of the time downhill with a following wind and clean hands).

    I would not give up on the Libre quite yet. See if it settles after a day or so and make sure you pay attention to the *average* percentage difference between BG and Libre scan rather than focussing on the odd scan here or there. After all the product literature is quite clear that if the scanned results don't match how you are feeling or seem odd you should check against BG, in just the same way that BG meter handbooks always say that if BG results don;t match how you are feeling you should retest.

    Hope your sensor settles to give you more like the 10% Mean Absolute Relative Difference that the Libre promises.

  20. Sorry Mike K

    I had a bit of a knee jerk reaction to my 1st problem :¬(
    I was a bit depressed with the tech :¬(

    I called up abbot (4 times) and showed them the straight line graph from 6.0 mmol to 1.9 mmol over 3 hours and they agreed it was a faulty sensor
    Before removed, it continued down to 1.5 mmol

    Also the system Event Log shoed many different errors over the 3 hours I had it on

    Seeing all this info abbott organised replacement straight away
    (including biohazard container to return the faulty sensor)
    good idea that because they can check what went wrong

    I have put the other sensor on now and will leave this on alone till tomorrow
    This one did not hurt at all when installing it (unlike the other sensor)

    Maybe I hit some bit of anatomy that caused it to malfunction

    Anyways Im a bit more optimistic now :¬) I will continue to report tomorrow

    Thanks for the blog :¬)

  21. I also wanted to say new Sensor seems to be working fine :¬)
    .5mmol higher than freestyle lite readings but is functioning
    I wonder what was up with the last one :¬)

  22. Does anybody know if you need a local ID national identification number to order on this 7 EU countries where you can purchase the FS LBRE online ?

  23. Not entirely sure what that means Anon, but I believe you can only get the product delivered in the country belonging to the website - eg items ordered on are tailored for (language/units) and can only be delivered to UK addresses.

    1. Thanks Mike K for your answer, in my case it will be Portugal, because I use the same units than Spanish, but my question goes to know if we will need, in my case, a Spanish citizen identification number (they are called DNI) , because if so, it will only be for Spanish citizens ...I hope I was clear enough ....I'm doing my best with the English ....Cheers, and thanks in advance, Alberto

    2. Apenas precisas de uma morada em Espanha e alguém que to traga ou envie para Portugal.

  24. Thank you for all the information it is very helpful as after emailing my interest in February 2015 I was told on the 3rd June 2015 that I will receive an email in the next 7 days giving me access to the online shop to order Libre.

    Just one question is the Libre affected by high temperatures (weather) as I am travelling to Las Vegas soon where the temperature will be 100+?

  25. Like all BG meters (and most electronic devices tbh) the Libre does have an operating temperature range the handbook lists these:
    Reader operating temperature: 10°C to 45°C
    Reader storage temperature: -20°C to 60°C

    I suspect it's a bit like a BG meter when you take it somewhere cold. Often they just grumble a warning and wait until you've warmed them up a bit.

    I'm guessing you mean 100F which is around 38°C, in which case you might be OK, but it would be wise to keep the reader out of direct sunlight and look for the shade wherever you can.

  26. Hi Mike - Are you still using the Libre and if so do you still rate it as highly as you did last year?

  27. Hi Bob

    I am currently lucky enough to be part way through a trial of the MiniMed 640G pump,complete with Enlite sensors (there are some blog posts about it if you are interested). If I wasn't I would certainly be wearing a sensor now, and probably would have worn one a few weeks back.

    So in short, yes, I do still very much rate the Libre and see it as an ongoing part of my arsenal of 'diabetes gubbins'. I tend to find that many times a sensor will allow me to fine tune things such that I can enjoy a month or so of relative stability. Sometimes more, sometimes less, but when thigs are behaving one sensor can help me out for perhaps 4-8 weeks before I start getting frustrated and need to consider wearing another. That's the way I've been using them this year. If money was no object I suspect I would wear one more or less permanently as I still find the accuracy *very* good for me and they are so convenient in so many day-to-day situations.

  28. Hello Mike,

    Do you think the freestyle libre is save to use/ rely on for driving a car/truck/motorcycle or would you prefer a regular meter in these situations ? Driving a 40 ton semi you have to know that the meter you are using is accurate.

    IF the libre would measure correct (all the time) it would be a huge step forward for finding/keeping a job, not to mension personal comfort.
    I'm not sure but I think I will give the libre a go and see how it goes, right now here in the netherlands they are looking if the libre gets paid from the healthcompanies. if not, when you use it for a year it would set you back about 1500 euros

    1. Hi Kay, You would have to check the regulations in your country, but in the UK no glucose measuring device that uses interstitial fluid (which includes the Libre and all CGM) are authorised for use by the DVLA to establish whether or not you are at the advised level to be fit to drive. This is largely because of the 'lag' between interstitial glucose and blood glucose which can lead to apparent differences when blood glucose levels are moving rapidly, but also because sensor glucose readings can be a bit out. Imagine if you disregarded 'feeling a bit hungry' because an errant sensor led you to believe that you were several points higher than you actually were. Doesn't bear thinking about!

      Even blood glucose monitors come with warnings to retest if a result does not match how you feel, because, as you no doubt have found yourself, two strips used in quick succession can occasionally give very different results. To my mind the Libre could be a useful adjuct to fingerstick testing, but it cannot replace blood monitoring.

    2. Hi Mike, thanks for your opinion. If the libre results were (much) more stable it would be great, but what I read from your blog, and others on the net the Libre is a step in the right direction but results vary too much to rely on and blood meters are still needed. Maybe one day we have accurate non invasive glucose meters.

    3. Personally, I think it's all a matter of margins for error - and I think that continuous monitors which are based on interstitial fluid (tissue glucose) are always going to have variances from blood monitoring, simply because the glucose in fluid around tissue cells does not react as quickly as capillary blood to changes in glucose concentration affecting the brain. It's just one step further removed. Blood monitors have their own margins for error too, of course - something like +/-10-20% from laboratory measurements being considered perfectly acceptable. And modern CGMs are within 10-15% of that much of the time.

      What matters to us, I guess, at the end of the day - is whether or not the data from any of these devices is useful in a practical day-to-day sense. And for me, the Libre is plenty accurate and consistent enough to give a helpful and usable feed of data that improves my self-management.

  29. I have diabetes 1 for 50 years. After trying a couple of devices, Navigator and DexCom I also tried Libre.
    It was very conveniant and I liked it a lot, but my experience so far:
    controlling sugar against AccuCheek Mobile LIBRE showed 1,5-2 mmol/l too low. This is like your experiences I guess.
    Abbott has to lower the values ! Or it should be able to reset the level after a bloodsugartest ?
    I always had to add 1,5 mmol/l to the numbers on my libre and that seems very unnecessary.
    Greetings from Norway
    Tom Blikstad

    1. My experience has a changed a little having run a few more sensors now. I have to say that out of all the ones I have run almost all of them have stayed firmly stuck for the full 14 days (only 1 I think needed a little over-taping) and only this second sensor has been that far out for that long. I'm not sure what it is that makes some people have more accuracy issues than others - but for me the Libre is pretty consistently hitting around 8-10% MARD, which means that almost all the data I receive is of the 'really useful' variety, with only a handful of outliers. Hope you have a bit more success and stability if you try a few more sensors Tom. Some people get more success if they insert the sensor and leave it 12-24 hours before starting (though this is positively discouraged by Abbott which suggest that this may impair accuracy). I have to say that the 'insert early' technique has given me some really good results in the first 24 hours of sensor life and means I don't get that really wobbly first day so often.

    2. I also find libre irratic at best :¬(
      1-2 low or 1-3 high (so softwares pointless)
      there is no calibration to blood pricks and it has "internal calibration" god knows what that is or how it measures what to calibrate
      overall out of 18 sensors in very depressed and spent a lot of money

  30. I haved used the libre for over one year now and loved it. However there seems to be an allergy issue with the glue on the inside connecting the housing with the adhesive plaster or the sensor material. After one year i became allergic and have had two sensors leaving quite severe wounds. I am going to try to have a barrier material or remove the plaster and replace it by double side adhesive tape and flexit or similar wound adhesive. See german you tube video.

  31. Having use the Libre on my son now for over a year, I'm thrilled with this technology, during the difficult tween years I've found my son is more likely to keep an eye on his levels with the Libre than with a bg meter, so much more affordable to set up than CGM....just wish it had the CGM alarms.

  32. This sounds as a dream to me... for about 1 year I'm reading comments of all you and just dreaming with my son's opportunity to use Libre. My son has 7 years old and about 3 years with DM1, but unfortunately this tecnology will delay to arrive in Brazil (only God knows how long). If someone may help me, I will be very grateful!

  33. I'm sure Abbott are keen to launch in Brazil as soon as they can.

  34. Hi Mike, I've just this week purchased the Libre for my daughter who is autistic; so not a wage earner due to her disability; are there any plans for the Libre becoming available on NHS prescription that you know of?

    Becca's Mum Chris

    1. Hi Becca, From what I can tell Abbott are working hard to make a case for the Libre to be available on prescription - at least for it to be on the list so that this is a possibility - if this happened, and because of the cost of the sensors there would most likely be some sort of regulation over who would meet the requirements for use so that the NHS's money is well spent, and for that they need good research data to make a compelling case.

      So the short answer is yes, but don't hold your breath, or expect it to be any time very soon - they are certainly working on it though!

  35. I am afraid out of the 18 sensors I have had 7 bad (replaced) left arm tends to show 1-2mmol lower and right arm 1-3mmol higher than blood pricks I had about 3 sensors that were "good" +/- 10% of Blood pricks

    also I observer serious increases in mmol reading when standing up from lying down position (vertical arrow)

    This makes a mockery of the superb long term 90 day analysis software and in my opinion this is not fit for purpose and should be withdrawn :¬(

    of course it could just be my fault (I have the wrong type of body or I ahve alien dna - the truth is out there

  36. Sorry to hear that you have had such a disappointing experience Bryan - from reading many others' experiences on social media it does seem that some people experience more accuracy/adhesion/reaction issues than others. I have no idea why. Some people still find they can use the trend data to good effect even if the numbers do not match finger stick BG, and others find that more erratic BGs and higher levels tend to have much more margin of error. Hope you find a way to make use of the data you get, or find another option that suits your body chemistry better.

  37. It has been usefull tool though it has helped me find the FOODS that cause bad spikes and I have trained myself not to eat them :¬)

    But as a trustworthy continuous monitor, it does not work with my body


  38. Hi is the libre compatible with the pump ?

    1. Hi Mad Mum

      Not entirely sure I understand your question. The Libre does not integrate directly with any pump on the market (nor can it in its current form as the integration that exists uses bluetooth connectivity that the Libre doesn't have).

      But it can be used as a stand-alone addition to pump therapy very effectively because of the depth of information it provides, which I find incredibly helpful for altering pump settings. You can also integrate your pump reports with Libre sensor for many devices (not currently Medtronic) using Diasend so you can see all your data in one place.

      Hope that helps

  39. Hi Mike. Great news for Brazil and South America: the Abbott started registration for those interested in libre. Besides is not available yet, they inform that will be soon. Probably this same process will reach other countries, I hope. The site is . Thanks for your initiative!

  40. Wonderful news Anderson! Thank you so much for sharing.

  41. If you want to see how it works, watch the video I made the very first day I received my scanner

  42. Thanks AD Kristina. We don't have the insurance issues you mention in your video in the UK, and Libre users here insert their own sensors whenever they want to use one (and can afford to self fund it!). This video by my good friend Dave 'Tangerine Diabetic' goes into more detail from a UK perspective:

  43. #freestylelibre genuinely awful service from @AbbottDiabetes. An innovative idea with no competitors is no excuse for faulty products and appealing customer service.

    Went through 3 metres, 5 sensors and hours of telephone calls do get this sorted and what do Abbott Diabetes Care offer me? Not so much as an apology.

    Their call centres feel like a bunch of people with exceptionally poor English going though a checklist and not actually listening. Seems like if its not on the form they don't understand it.

  44. Just started using the libre freestyle. On my 5th day and so far results are flaky at best. Averaging 2 mmol lower than my BG meter. I really like the concept and attempts to moves us away from the archaic finger pricking but I will not give up my BG meter just yet. I have a 6 month supply of sensors so I will continue my trial of this product inconjunction with my BG to keep my A1c tight.

  45. Hey there,

    I have been using the Libre for about 10 days now in the U.S. (A friend in Italy buys it and ships it to me.) When I plug the cable from the reader to my computer NOTHING comes up and I am at a loss what to do next. Can someone share a UK help number for the freestyle libre, and also any ideas for troubleshooting?

    thank you!

  46. I don't think the Libre mounts as a standalone device. You need to have the Abbott Freestyle Libre software installed in order to download raw data from the handset or create the PDF reports. Are you able to visit

  47. I am locked out when I go to the site. I tried. But two other US users said that something launched on first plug in. And the device doesn't come with any software. So frustrating. Perhaps someone can email me the software to install?

  48. I am disappointed. Big difference between patch/sensor (Libre) and strip(Accucheck or FreeStyleEasy) is bigger than 70mg/dl most of the time. Deviation is bigger than 15%.
    I changed the reader with a new one, I changed the sensor and same thing. It is any chance to recalibrate the reader? Maybe the manufacturer can provide some troubleshooting for this kind of problem.
    This product is not cheap and is not available worldwide to chnage it everywhere. Also, I'm using now 2 devices to check my blood sugar, Libre and Accucheck.
    Is very annoying when Libre is showing LO (very low level of glicaemia/ blood sugar) and Accucheck is showing >100 mg/dl.
    So,what is the achievement.

  49. Sorry to hear you are getting a greater difference between fingerstick BGs and Libre data than you would like. Here are my thoughts on some of the issues:

    1. The devices are measuring 2 completely different things, and processing the raw data through different algorithms. There will *always* be differences. Not every reading will be <1mmol/L different, but several at <0.5mmol/L different may bring a sensor average into acceptable performance 'MARD'.
    2. ingerstick BG data is allowed to be +/-15%. Without living in a lab you can't actually know which of the devices is reading most accurately for any one test
    3. When my BG is more erratic, I am much more likely to see larger differences (the Libre tries to predict 5-10 minutes ahead based on recent data).
    4. Some sensors *are* going to be faulty. Where you have ones that read consistently way off fingerstick BG more than 48 hours after insertion it is worth contacting Abbott who will troubleshoot the sensor and may replace it if they decide it it not performing as expected
    5. Confirmation bias is a tricky thing. Often I think a sensor is misbehaving, but when I actually look at more data from it and average it out I find the differences (after the first few days) are nothing like as large as I had thought
    6. It's about trends and usability of data. If you find the numbers themselves too far off, but the trends useful then you might decide to continue. Alrternatively you might decide that one dodgy sensor every so often when most of them are spot-on (this is my experience) makes the device a powerful part of your diabetes toolkit. Alternatively you may decide that you never seem to get data that you feel you can rely on and that the Libre is not for you.


  50. I have just started using this and after the first day, have found most of the readings to be "lo" despite capillary blood sampling being 4.5mmol/l. Not much use so far. I have tried a few CBG monitoring devices over the years including Medtronic's and Animas' (I know libre is not strictly speaking CBG, but it uses the same technique of monitoring interstitial fluid as CBG does) and have found them all so far to be a bit hit and miss and variable from one sensor to another. I have had sensors that have been pretty much bang on for most of their lifespan and others that have been totally inaccurate from the moment they are implanted and never improve.

    Unfortunately, it looks like this libre system is going to be no different - unless it improves significantly.

    I do think the idea of not including the possibility of calibrating is a mistake; I appreciate the reasoning and sales pitch behind it but Abbott seem to be under the illusion that the aim is total absence of finger prick testing (that's how they've marketed it, with this as their unique selling point), whereas I would think that for most diabetics this is a secondary concern and that accuracy and 24 hour monitoring is actually more important: I am sure most diabetics wouldn't mind doing the odd calibration with capillary finger prick testing a couple times a day if it meant better accuracy. Their USP could just be that it's at least about 50% cheaper than any other CBG systems and probably more :)

  51. After I accidentally dislodge my patch of more than a week, I put a new patch and waited for an hour to get my first blood glucose reading but all I get is "LO" result. I tried to use my old glucometer and it shows 122mg/dL result. What could be the problem here.

    1. Some sensors take a day or two to settle in. If it is still reading significantly different (more than 50-60mg/dl different) to fingerstick tests after 48 hours I would contact Abbott who can troubleshoot the sensor and may offer to replace it.

  52. I've been trying the Libre and I love it! It really helps me see what is going on at night and it actually forces me to face my blood sugar challenges head on(because it collects data all the time, even when I am too scared to go and check it as I think I might be high). But I suspect I may also have a lost a sensor to security gate "nuking". Everything was fine, I popped to the shops and when I got home it didn't want to know anymore :-( I suspect it was Boots as I think they RFID tag some of their more expensive items. Or maybe I was just unlucky and got a a dodgy sensor. I'm going to try a new one then go back to the same shops on day 14 of its life to see if it happens again!

    1. I have heard of people getting problems with some public library scanners. Might be worth contacting the Abbott Helpline to ask their opinion/advice?

  53. Since wearing the sensors I have set off the scanner alarms in a few shops and had not made the possible connection until today. Emptying my shopping bags is becoming increasingly embarrassing. However my sensors do not seem to have been affected/ still seem to be working - ...???

  54. I have been using the sensors for 6 months now and continue to experience a large number of LO moments. Each time I check with the finger prick and those readings have never been below 4. This is a real problem as I found myself taking on sugar to move out of LO territory only to find myself then too high. Indeed the first couple of days the sensor is not too accurate (which is a big proportion of a sensor's life). I had a long LO and ignored it thinking it was the new sensor that was wrong. Two hours later I had paramedics around me. My averages are coming down now that I use the sensor but part of this is because, like today, I have been LO all day (even though I am not). Today is day 11 of the sensor, which I will now bin. Most sensors do not survive 14 days - mine seem to range between 7 and 12 days. They are sticky but not if you sweat it out in the gym - I use Opsite surgical cling film to cover the sensor, which seems to help a lot.

    The readings seem to be around 30 minutes behind live status - I often feel good / bad long before the meter tells me.

    On balance, the sensors are good but seem very inaccurate at lower readings and this is not good enough for careful management.

  55. Anonymus 14 June mentions using Opsite surgical cling film. I normally swim for between 1 and 1 1/2 hours, while Abbott advises no longer than 1/2 hour with a sensor in place. I have not yet been swimming with the sensor. Could this film be used to keep it from coming loose for longer than 1/2 hour? Has anyone had experience using the Libre sensor in a swimming pool (swimming lengths)?

    1. I have seen varying reports of success/failure with people spending longer than 30 minutes in water. Some people seem to get few problems, with to without overtape, while others don't even seem to be able to make it to 30 minutes! I've certainly seen posts on the Libre Users Facebook group where kids have had waterpark holidays and been fine for well over an hour. I guess part of it will be down to how well the adhesive stays put for you generally, as this does seem to vary slightly from person to person. As for tapes, I have used Opsite in the rare event that a sensor seemed to be coming loose (though that's only 2 sensors all the time I've been using them). Others use hypafix, tegaderm or kinesiology/sports tapes or rock tape. Hope you find a solution that works for you. Let us know how you get on and what you end up using.

  56. First day using it, from Portugal, I confirm the low values in comparison with the one touch verio strip tests. I get 62 mg/dl in the libre reader and 96 mg/dl in the verio system.
    But the arrow mode rocks! You can finally know what's going on!

    1. Translation: "You only need an address in Spain and someone to bring or send to Portugal."

  57. Anonymous 14 June 2016 mentions using Opsite surgical cling film to protect his/her sensor from moisture. I swim for between 1 and 1½ hours once a week, whereas Abbott indicates ½ hour as the maximum time a sensor can be relied on to stay in place while swimming. As a result, I have not yet tried swimming with a sensor in place. Has anyone experienced swimming with a Freestyle Libre sensor? Has anyone used Opsite film or any other (similar?) product to protect their sensor? Will it extend the time you can swim without the sensor becoming detached? The try and see option is risky and I would rather not miss a week’s swimming to wait until the 14th sensor day. Any advice would be welcome!

    1. Please see reply to your earlier comment.

    2. Sorry about that. I hadn't seen that you had already answered my question. I will report my experience after swimming.

    3. Anonymous from 9 July again: Here's my report after swimming!! I swam in a public swimming pool for roughly 1 1/2 hours on the last day of my first sensor. After swimming my sensor was still reporting accurately and continued to do so until it ended later in the day. In fact, my only difficulty was in removing it as it was still so firmly in place! ( Perhaps I should note that I have no hair on my arm and sweat very little.) I will let you know if anything changes. So far, so (very!) good.

    4. Thanks for the update Anon! Sounds like it's working really well for you. :)

  58. Thanks again for the write-up Mike, and thanks everyone here for the great discussion that spans quite a while.
    The Libre just made it to Israel, and I'm meeting the representative tomorrow for a first hands-on tutorial [and to pay the exorbitant price :/].

    I also spoke to my doctor about it this week, he warned me that the Libra will have a constant gap between its readings and blood glucose.
    He said that in his experience, in the trial here in Israel, the gap - once confirmed - was pretty much constant thought the life of the sensor.
    If that's the case, then you can always calculate what the proper reading would be, and it shouldn't be a problem.

    Did anyone here experience this?

    1. Thanks Rubio - in terms of the sensor lag, I think this is a more precise and numeric interpretation than I have seen in practise. Sensor glucose and blood glucose are varying at different rates and I think even things like hydration can affect the rate of change, so I would not expect to be able to establish a concrete 'rule' for difference between the two any more than I would expect to be able to establish a concrete rule for anything else diabetes-wise. The algorithm in the Libre handset aims to reduce the sensor lag to more like 5 minutes rather than the usual 10-15, but I have noticed a substantial delay when recovering from mild low blood glucose. Fingerstick can be well up at 5-6mmol/L and sensor still reading <4. All of that is in the documentation though - and you soon learn not to double-treat off Libre readings. Very obvious - but well worth bearing in mind that the more unstable/erratic your BGs are being on any one day the greater difference between sensor glucose and fingerstick BG you are likely to see. When my BGs are better behaved I notice almost no gap/difference at all and personally I'm happy to dose or correct from Libre readings quite often.

      Hope you get on well with it :)

    2. Thanks for the quick response!
      I'm 35 now, almost 36, I've never sought any kind of support group, I don't even have a preferred doctor/nurse helping me out consistently. I've had better times when my A1C was 6.5, and dark times where it got up to 9.5, but I've always done everything by myself.
      I don't think I can go on like that any more - I know to get back on track I need some support. I found a doctor I like, and I'm starting with the Libra just to get back at least a feeling of being somewhat in control.
      I'm not even sure why I'm writing all this - I guess I just was a bit overwhelmed by finding your blog and the great community you foster. I'll definitely check back in :)

  59. Just put my first sensor in yesterday, and done a lot of doubling up of meter readings and libre readings. Too early to male sense of any patterns, but as yet I don't 'trust' the libre but I will persevere.

    I have used a dexcom cgm with my animas vibe pump before which was sensationally good for building understanding and improving control. I only had two problems with this. One was simply the cost (UK = not NHS funded), the second was that as I do a lot of distance running, the cgm would fall out far too frequently. Im hoping the libre sensor will stay in place better as its in my arm (I'll find out when I run this weekend), but I cant understand why Abbott haven't given an option to re-calibrate the unit from a BG result. I have to say also the current freestyle website is horribly glossy, it doesn't work properly on some mobile devices, registration didn't work properly and there was no response from their 'contact us' page - I had to find a generic helpline, and they should really be hosting some sort of moderated blog to help us users work through the issues we encounter and to provide tips and helps. Im going to stick with it for a few weeks though as overall I think it will help improve my control and understanding of whats going on.

    1. Hope it works well for you SmartMart. If you are on Facebook there is a large and thriving Freestyle Libre user group which you might find interesting -

    2. Thanks Mike - I'll get on to FB this evening, and thanks also for your very good blog here!

  60. When I used the sensor a message appeared saying:
    "This Sensor cannot be used with this Reader."
    How can I fix this problem? And what do you think caused the problem?
    I need the answer as soon as possible please.

  61. I'm not sure - it is not an error I have seen, but I think that *might* be the error that occurs when you try to mix sensor and reader from different countries? Are you living in a country where Libre is not officially released and buying various bits from eBay or whatever?

  62. Hi there!
    Is there any way to continue reading from the same sensor after more than 14 days?
    Thanks in advance!

    1. No. At least not that anyone has found so far to my knowledge. The sensor and reader are tied to the 14 day limit. There were rumours that one of the unofficial apps was able to read for an extra few hours, but that seemed also to occasionally fry the sensor mid-way through its life. I think the 14-day life might be hard-wired into the sensor in some way - either that or the tiny battery in the sensor just doesn't last much past 14 days of activity.

  63. Hi. I have been using Libre for quite a while and my experiences are quite similar to yours. First two days are usually lower by 1.5-2.5 than my finger readings. I have read on aome blogs that people tend to put in the new sensor 24-48 hours before the old one ends without activating it so it gives it these 2 days to calibrate itself without waisting this time for misleading readings. I haven't tried it yet but will on the next sensor change.

    1. Thanks Marta. Yes I've come across that too. Most of my more recent sensors I have inserted 12-24 hours before activating. I can't say that I know for certain whether it has been better, but I have had most sensors well within acceptable limits for me - certainly after the first day.

      Interestingly, having spoken to some of the Abbott technical peeps, this is *very much* not recommended by them - they even suggest that it might degrade sensor performance. Something to do with the chemical reactions around the filament which are different in some way when the battery/sensor is activated I think. Whatever your experience, do bear in mind that the people that make the thing think it's a bad idea.

  64. Hi

    Thanks for a detailed overview.
    Sounds good enough to try from the measurement point of view.

    Could you comment on the wearing experience?

    Are there any other spots (rather than upper arm) where you could insert sensors?
    I am concerned with what happens when you do exercises that involve triceps.
    Will the muscle contractions bend the fiber, which is part of the sensor (like it happens with insulin pump cannulae)?
    Can it become painful (during the contraction)?

    Also, water resistance: 30 min (or so) in the water.
    Will the sensor break after that or become erroneous? or it will just start peeling off (in which case taping it over as suggested is good enough).

    Another surprising thing is that the sensor can last for 14 days. Was there any inflammation? (again, it happens with cannulae after 3-4 days, so how can the sensor here withstand 14?)

    Your post is rather old, so I presume you self fund your Freestyle Libre.
    I was told by a nurse that although Libre is not funded by NHS, one can negotiate that, providing evidence that it is cheaper than the test strips.

    I use about 200 test strips a month, which is ca. £120 (retail price), which comes just a little more expensive than 2 Libre sensors per months.
    But this is retail price!
    Do you have any clue as to whether the NHS pays the retail price on both, test strips and the Libre sensors?

    I would appreciate if you could comment on any of my queries.
    Thank you!

    1. Hi Unknown

      My wearing experience has always been very comfortable (see image above for before and after 14 days wear). However some people seem to have problems with developing a sensitivity to the adhesive and/or sensor removal. Hasn't happened to me yet, but I've seen some gooey Facebook images. Other people seem to have skin types that do not take the adhesive so well and need to overtape. Again, not my experience, just things I've seen on the FB Libre group.

      I know people have used abdomen, thigh and chest with varying degrees of success for different people. Abbott only recommend back of arm though.

      I've not been swimming with a sensor on, but have seen good reports. Some people have had success with longer than 30 minutes - but others have had failures/sensors falling off (as seems to be the case with some people and high intensity activity/perspiration).

      Not very helpful, but I'm afraid the answer to most of your questions is it *might* work for you, but the only way you'll know is to try it.

      NHS pay significantly less than retail cost for strips. The main obstacle to your plan is that the Libre is simply not available on prescription. There is no payment channel that exists yet. Things are moving in the right direction and reimbursement is being 'actively pursued' - though I gather Abbott have now formally begun the necessary process.

      Hope that helps - if you are on Facebook you might find the Libre Users group a useful source of information.

  65. Hi Mark, thx for helpful insight - I'm just after my first sensor and found it suprisingly accurate - perhaps the beginner's luck but result are within 5% range of finger test most of the type, apart from strong hypo - then Libre tends to fail.

    Still - I'm writing to find out if anyone had same trouble I now have with the second sensor - it's on for 2nd day now but the reader does not show any graphs now - no info about levels from in-between scans - only dot-data form when I did the scan myself, not the full-picture constant data that the first sensor provised, so helpful esp. at night. Did anyone get that trouble? Local abbot help phoneline is hopeless,

    rg, paul

  66. My experience of the Freestyle Libre sensors, used with my Samsung Galaxy S5 Neo and the Abbott Industries App, has been very negative - although the first few hours were fun and gave me some great insight. The problem is that the sensors are just too easy to dislodge and they CANNOT BE RE-ATTACHED - not even once. I say that in CAPS because Abbott Industries don't want you to know that your £50 is wasted once the damn thing won't stick or gets the slightest knock in the shower. They will not refund because, get this 'the seal is broken'. How you are supposed to get it on to see if it works without breaking the seal, taking it out and sticking it on your arm, they failed to explain. My sensor only lasted a few hours before getting the slightest of knocks on the door frame as I walked through carrying a tray. The Freestyle Libre Sensors cannot be reapplied once they come out. I repeat. the Freestyle Libre Sensors CANNOT BE STUCK BACK ON they are single use, if it comes off your arm at any point in the 14 days (the could see I had only had mine ONE DAY) you have give Abbott Industries another £50 for a new one!!!.
    If it gets knocked out, Abbot Industries will, if they bother to answer at all - (they ignored my first three emails to customer services for a week despite a quoted 48 hour response time) simply quote their terms and conditions at you, saying that it's your fault for "damaging the item". The sensor was not and is not damaged in any way, it was still half stuck to my arm, but no longer gives readings and so is a £50 waste of money. So, inaccurate readings - don't know. Appalling customer service, definitely. Waste of £50 I can ill afford, yes.

    It's a serious design fault and one that the company would appear to be aware of....

    Why else turn away some £65,000 per user for a simple £50 refund?
    1 diabetic using one sensor per fortnight @ £50 per sensor for 50 years is £65,000 revenue to Abbott Industries. Even a years use would be £1,300 to them - If these sensors stuck properly, they would hardly ever come off, refunds or replacements would be negligible in cost and so they would, sensibly, replace them in this rare event. If, however, as I suspect - they have a HUGE number of Libre Freestyle sensors coming unstuck and customers asking for replacements - it would be a huge cost. It must be a HUGE number for them to NOT offset it against the potential £65,000 per patient that they are likely to receive.

    It's my belief that if they had to refund every faulty sensor and every sensor that gets knocked off / washed off / won't stick (the forums are full of tales of woe) that Abbott Industries would go bust and so they are now telling their previously allegedly very helpful customer services staff to refuse refunds.

    Avoid the Abbott Freestyle Libre at all costs - it's a great gadget, with huge potential, but has a design flaw that the company won't take responsibility for and that is hugely expensive.

    1. Hello Diabetic Diatribe

      Sorry to hear you had a 'doorframe incident' with your Libre sensor, and particularly sorry that Abbott did not replace the sensor for you. In my experience, and seeing what goes on in the Facebook Group of over 5000 members across Europe this seems quite rare. I have heard of people not getting replacements after multiple problems in quick succession, but many people are able to get a replacement (even when it was parents using on under 18s before the lines was given for paediatric use). It's disappointing that you didn't - and as you point out they have lost your custom.

      Regarding the adhesive, it seems to me that there must be some variation with skin types or something. Some people complain of sensors not sticking, others complain they can't crowbar the sensor off after 14 days. Some people use a variety of overtapes or skintac preps to help secure them and others (like me) never have a problem.

      It's a weird one for sure.

      Having said that I have been using an insulin pump for several years, and one thing I noticed with the infusion sets for that is that the adhesive seems to take around 12-24 hours to come up to full strength. If I do too much bending or stretching with a new set on sometimes I can feel it sort of 'give' and then that's it - the sensor is loose and hardly stuck on at all.

      As a consequence I have always made sure I'm careful with sensors and make sure they don't get knocked if I can possibly help it for the first day, particularly the first few hours.

      If you decide to have another go with Libre I hope you get on better with it. And I wonder if it might be worth contacting Abbott again and seeing if you got a different response from a different person. Incidentally the email-response is renowned for being rubbish. You are far better off calling them and talking things through.

      Thanks for reading!

    2. Just seen this on the freestyle users FB page. Seems like you should be able to get up to three replaced for no reason whatever.

      Abbott policy on replacing sensors:

      "As stated in our UK terms and conditions of sale, we offer up to three free replacements as a gesture of goodwill where there is no suggestion that the sensor is faulty. The FreeStyle Libre sensor has a wear time of up to 14 days. This is dependent on many factors including your skin type and the activities you undertake while wearing a sensor and if a sensor falls off for these reasons the sensor is not considered to be faulty.

      There is no upper limit on the number of sensors that will be replaced if Abbott UK suspects a fault and if the product is within the expiration date and used as directed."

    3. I use tagaderm which solves this problem. They used to just fall off. No problem with tagaderm

  67. I have worn 3 libre sensors & had no more than 5 days readings on each as they come unstuck so easily .
    I have worn a pump successfully and had no problem with the infusion sites
    It's expensive for 5 days readings £10 a day
    A little disappointing to say the least
    I loved have the ease of testing and would love some tips as to how I can keep them in my arm
    Would I be able to wear it on my stomach as bra straps & doorways seem to be causing the problem !!!

  68. Dear Mike,

    This is great site. Fantastic!. Reason I'm commenting is that my Libre has been consistently recording higher readings than my BGM, sometimes topping 50% more than the BGM reading. Last night I had a pretty bad hypo, because the Libre check was reasonable high, but I suspect the BGM was significantyl lower. I didnt do a BGM before going to bed which I should have done, and the day before I went to the gym (always has a knock on effect for me). What do you make of this Mike? Any one else had consistentñy higher readings on the Libre?

    1. Hello Anon, Not consistently no. Sometimes I get a sensor that tends to read a little high to begin with, sometimes I get a sensor that tends to read a little low to begin with. But these mostly settle down within a few days. In the years I have (intermittently) used Libre I have only felt 2 sensors were reading so significantly 'out' that I have asked for a replacement. Mostly I get results well within usable parameters *for me*. That's not to say that every single Libre result matches every single BG result - it can never do that - some can be out by 2mmol/L occasionally. But if how you are feeling doesn't match that the Libre tells you Abbott are quite clear that you should trust BG as being more immediately reflective of your actual BG if it were measured in a lab. Hope you sensor settles down for you. And yes - you are right exercise and activity can have quite a knock-on effect for 24-48 hours. Personally a BG measurement before each meal and another before bed would be my bare minimum BG checking routine. Not sure if that would change if I wore Libre full time.

  69. I do have consistently higher measurements on Libre when there is a reason for a rapid drop. E.g. long term exercise, large bolus (with fast acting carbs).
    So I already know, that if Libre shows 5.0 and going down rapidly that means that BG is about 3.5 already and going further down.
    Remember that Libre measures glucose in interstitial fluid, and therefore there is a lag (that depends on many factors such as your metabolism, affected by recent exercise).
    So you CAN NOT treat it as a usual BG measurement, but instead, formulate other rules, specific for yourself (such as 5.0 and going down rapidly means hypo in my case).

    If there is no reason for a rapid drop then the measurements a pretty damn accurate! at time with just 0.1 difference between Libre and BG

    Again, this can be individual.

  70. Thanks Mike and Anton. Very helpful. I note what you say Anton about a rapid drop. Whenever that happens, the chart I've done over the last 5 days shows that gap between BG and Libre widens. Conclusion: no chance soon of doing away with my BG. If a go back to blood tests before every meal, as Mike suggests, then I wonder if the expense and hassle of the Libre is worth it.

    1. I am just trying it out at the moment, but I believe I can go down to 1 box of usual test strips + 2 sensors a month (currently I am using 4 boxes a month). Price-wise in would be almost the same, but much more information about sugar levels. 1 box a month (50 tests) would be enough to validate the Libre results in suspicious cases.

  71. Hello Mike,
    Thank you for your detailed facts expressed in easy narration.
    I am using the sensor and the reader for my father, in India. I found it is very helpful in regulating sugar levels. It's a boon for me. It has entered in India very late. Still this reader needs some improvements. Lastly, I have a doubt. If could throw some light I shall be happy. Is there any relation between Type-2 diabetes and Sun rise?
    Thank you again.

  72. It is learnt that 'Fitbit' has released a wearable gadget in collaboration with 'Medtronics' for blood glucose reading. Is it true? any idea?

  73. Interesting reading. MY reason for searching the Web was looking to find whether other Libre users have had issues with APPLYING the sensor? I've had 9 successful applications BUT a further 3 that simply did NOT register; I'd call a 33% failure an issue! BUT I have one common theme: ALL in my left arm &, as a left-hander, wondering if stronger muscles an issue? Poor right-hand application method? Lack of muscle tone? FYI I'm 62 and NOT into gym, so more likely getting old, flabby skin..but that is on BOTH arms...and never an issue in my right arm, where I now have current (successful) sensor placed.
    Accuracy: agree with all the previous posts: the readings DO vary from finger-prick but I really do like the trending feedback I now get: have pruned my (Levemir) basal dose to half of pre-Libre days; recalibrating my (Novorapid) meal ratio shots; can now "see" my morning syndrome highs and currently working to control a lot of good stuff, other than the panic attack each 14 days, wondering if the next sensor is going to fire up: at $92.50 ea, being told by machine to remove the just-installed sensor and replace with a new one ( assuming one HAS a spare!) is tedious as well as expensive, though, for now, Abbott have been prompt in replying to my complaint, and sent out a replacement ( by DHL so one HAS to be home to take delivery: delivery / lack of over-the-counter availability a gripe for another time

  74. Anyone had a considerably large variation between libre sensor reading and reader reading/or neo?I've found the difference can be up to 3.0 moll in difference usually my actual blood sugar is lower but the libre gives a higher reading.this can happen a lot for no apparent the actual reader the problem?

    1. There are so many reasons why sensor glucose and finger stick glucose can be different - and one should not always assume that finger stick is 'right' and sensor 'wrong' - they both have significant margins for error.

      Sensor glucose is likely to lag behind finger stick values. And you will see much greater differences when BG values are changing rapidly.

      If I suspect a sensor may be performing outside of the expected tolerances, I find it helpful to re-examine relative paired differences over a fairly long period (say a couple of days) and to make sure that I'm using pairs when BG was fairly stable as well as those then things were a bit more wobbly. I'm often surprised at how close many of the values have been, because I don't really clock the ones which are 0.5 out. I only notice the few where there is a bigger difference, so it feels like they are more frequent than they are.

    2. Also worth pointing out that any continuous/sensor system will work differently for different people, and some just don't get on with Libre for whatever reason. Others will be fine with Libre (or Medtronic or whatever...) but get terrible results from Dexcom. You just have to try to find the one that works well for you.

  75. Hi! There are 13 months I'm using in my son, so there were about 27 sensors we used. I've never had another experience with another blood glucose meter. We learn to use freestyle libre when in the pool or at sea (using a wrist protector), to make it more "animated" (with children's stickers) and to accept it problems. Freestyle is good, but, it's not always accurate. Some sensors measure up, others measure down, others delay correcting blood glucose after a low glucose event, two caused bleeding in the application (much blood we were worried!!) and I have had two that failed and did not work (and were replaced by Abbott). Despite these inaccuracies, given the age of my child and our economic conditions, it is still the best option for us.