Libre 2 Accuracy - When to Contact Abbott?

[CivicFreak]

I have been using the Libre 2 for a couple of months now, and apart from early teething troubles I've really come to like it and for the most part the accuracy seems to be fairly in line with my finger prick readings from my meter.

However my current sensor (I applied it last Saturday) seems to have gone a bit awry over the past couple of days. When I first put it on the readings were reliable but I've noticed over the past 2 days the readings have been drifting further from my BG readings. My first inkling that something wasn't right was that after eating my tea my sensor indicated my glucose had dropped to below 3 - yet I felt perfectly fine (I normally recognise the signs of a hypo very well). Checked with a finger prick and I was actually above 5. This morning I scanned my sensor again and found that according to the readings I essentially had a hypo which lasted all night - first reading this morning was 3.7 but finger prick showed I was actually 7.9 - a massive difference!

Just before posting this thread I scanned my sensor - reading of 7.2 but finger prick reads 11.5 so I'm feeling that the data I'm getting from my sensor cannot be trusted. Is this a common thing? Should I be getting in touch with Abbott about this and getting a replacement sensor? Feel like I'm answering my own question really, as I already know I can't trust the readings I'm getting, but just wondered if this was a common thing, and if it is, how exactly can we ever really rely on the Libre in the first place?

 

[helli]

@CivicFreak I would not say this is a "common thing" but it happens.
In your position, I would be contacting Abbott and have evidence of differences to hand.
You can show that it is out by a long way and that you are at risk of missing hypos which they should take seriously.

 

[CivicFreak]

@CivicFreak I would not say this is a "common thing" but it happens.
In your position, I would be contacting Abbott and have evidence of differences to hand.
You can show that it is out by a long way and that you are at risk of missing hypos which they should take seriously.

Wow that was a fast reply!

Glad to know it's not common. In honesty I've found it to be fairly reliable in my short time of using Libre 2, but this one was a bit concerning. Appreciate the advice 🙂

Also I agree that it's highly likely I could miss a hypo which is worrying to say the least. I normally recognise a hypo but I know there are people that don't, so it could quite easily be a serious issue were the same thing to happen to those people. Equally, I could be thinking that my levels are good when in fact they are high and need correcting as they are this morning.

 

[rebrascora]

I try to assess my Libre's accuracy when my levels are stable for at least half an hour rather than after a meal or perhaps in the morning if you are seeing a rise due to DP. I assume you are aware of compression lows which can cause the sensor to show hypos through the night if you lie on it.
All that said, it sounds like you have a dodgy sensor. It seems to happen more frequently to some people than others with Libre 2 and there is no clear understanding of why. I hope you are not one of those people and this is just a one off rogue sensor.

 

[CivicFreak]

I try to assess my Libre's accuracy when my levels are stable for at least half an hour rather than after a meal or perhaps in the morning if you are seeing a rise due to DP. I assume you are aware of compression lows which can cause the sensor to show hypos through the night if you lie on it.
All that said, it sounds like you have a dodgy sensor. It seems to happen more frequently to some people than others with Libre 2 and there is no clear understanding of why. I hope you are not one of those people and this is just a one off rogue sensor.

Yes I do the same thing for the most part, which is how I knew something wasn't entirely right with my readings. I am aware of compression lows and an particularly mindful of these given I also wear a band during the night to help protect the sensor. I haven't noticed any compression lows though, since I have the sensor on my left arm, but I tend to sleep on my right hand side but it's definitely something I take into account.

I am hoping that it's just a faulty sensor though, as my others have been good so far - mind you I've only actually used 4 or 5 in total since I moved over to Libre from finger pricking alone. It's certainly bizarre how it occurs more frequently in some people than others - perhaps the sensor is very sensitive to positioning on the arm and the amount of "fleshy" area it is attached to. I am relatively slim and don't have much fat on my arms, so it's difficult to find a good position - perhaps on this occasion I have found a less than ideal location? I also don't alternate my arms as I am not keen on the idea of putting it on the arm I know I will be sleeping on.

It doesn't shake my confidence in the Libre though, but is interesting nonetheless.

 

[Lisa66]

Hi
I’m about to ring Abbott about exactly the same issue. The vast majority of sensors I have used ( for a number of years now) are pretty accurate…but I get an occasional “off” one, this sensor is reading around 3 lower.

If you haven’t called Abbott before have some info ready for when they ask, as it saves time and faffing around.

They’ll ask for the Libre serial number…it’s on the box or container if you still have them. If not it’s listed in the “About” info on your phone / reader. Keep that open as you call as they may want software info etc which you can find here.

Abbott are very helpful, so don’t hesitate to call them with any issues.

 

[CivicFreak]

Hi
I’m about to ring Abbott about exactly the same issue. The vast majority of sensors I have used ( for a number of years now) are pretty accurate…but I get an occasional “off” one, this sensor is reading around 3 lower.

If you haven’t called Abbott before have some info ready for when they ask, as it saves time and faffing around.

They’ll ask for the Libre serial number…it’s on the box or container if you still have them. If not it’s listed in the “About” info on your phone / reader. Keep that open as you call as they may want software info etc which you can find here.

Abbott are very helpful, so don’t hesitate to call them with any issues.

I have just this minute finished talking to them (I say talking, I used the online chat). As advised by my DSN when I started Libre, I keep the lids with the serial number on just in case they are needed. Was quick and easy, they're sending me another sensor, but luckily this was the first of my new prescription so I have a spare to last me until my new one arrives.

Interesting that you are also having a similar issue with your sensor reading 3 lower. I wonder if there's maybe a faulty batch perhaps?

 

[trophywench]

Apparently it's also on the edge of the sensor itself, but unless you have an eyeball on the end of your pointing finger on the other hand - that's of limited use to most people unless the user is a child and you're their mum!

 

[CivicFreak]

Apparently it's also on the edge of the sensor itself, but unless you have an eyeball on the end of your pointing finger on the other hand - that's of limited use to most people unless the user is a child and you're their mum!

I guess they want to make sure people will always be able to find it no matter what!

Just checked my finger tips and nope, no eyeballs. I think people think I have eyes in the back of my head, but definitely not on my fingers 🙂

 

[helli]

Apparently it's also on the edge of the sensor itself, but unless you have an eyeball on the end of your pointing finger on the other hand - that's of limited use to most people unless the user is a child and you're their mum!

I can read the number on the side of the sensors without bionic eyes or eyes on the end of my fingertips.
That said, I prefer to get the number from the app as I do most things with my phone and find this quicker.
If I did remember to keep the box lid, I would have no idea where I put it ... unless it was somewhere that was inaccessible at that time. I guess you could take a photo of the box lid with your phone.

(If you are using the reader, the sensor number is available somewhere on the reader UI and the call centre team can walk you through finding it if you are unfamiliar.)

 

[Bruce Stephens]

If you are using the reader, the sensor number is available somewhere on the reader UI

It's in settings->System Status->System Info. That shows the last three sensors and (as in the app, where it's in About) they're in reverse order, so the first one listed is the current one.

 

[Lisa66]

Seems we were chatting to them at the same time @CivicFreak

It will be interesting to see if the other sensor, that I got at the same time, has the same issue. I’ve not had issues with two in a row before.

 

[CivicFreak]

Seems we were chatting to them at the same time @CivicFreak

It will be interesting to see if the other sensor, that I got at the same time, has the same issue. I’ve not had issues with two in a row before.

Yes I wondered this myself. I assume that the 2 I had would have been from the same batch as I got them at the same time.

I'm waiting for my replacement sensor from Abbott but I had the second sensor from my prescription so am using that. Seems better so far - it's reading around 1mmol/L lower than my finger prick meter, which is acceptable for me. Will see how it goes over the next few days.

How is yours?

 

[Lisa66]

Seems ok so far.

 

[CivicFreak]

Seems ok so far.

Good!

Mine is kind of a bit unpredictable. Sometimes it is pretty much the same as my meter, then another time it can be 2-3 mmol/L out. Not sure what's going on. I think for the most part though, it's close enough, but I still don't feel I can 100% rely on it.

 

[helli]

Good!

Mine is kind of a bit unpredictable. Sometimes it is pretty much the same as my meter, then another time it can be 2-3 mmol/L out. Not sure what's going on. I think for the most part though, it's close enough, but I still don't feel I can 100% rely on it.

When is your sensor less accurate?
I ask because there are limitations of the Libre (and most CGMs) which have been repeated many times of the forums.
I find the sensors unpredictable on the first couple of days after insertion and can be 2 or 3 mmol/l out when reading high. This is why it advice is to always check a high (or low) before treating. But I find them to be fine to dose from at "normal numbers" when I have given the sensors a couple of days to bed in.

 

[CivicFreak]

When is your sensor less accurate?
I ask because there are limitations of the Libre (and most CGMs) which have been repeated many times of the forums.
I find the sensors unpredictable on the first couple of days after insertion and can be 2 or 3 mmol/l out when reading high. This is why it advice is to always check a high (or low) before treating. But I find them to be fine to dose from at "normal numbers" when I have given the sensors a couple of days to bed in.

That's something I am trying to pin down because there doesn't seem to be any pattern to it. I would love to say it's always first thing in the morning, then maybe I could put it down to compression low or something like that, but it's not. For example yesterday morning before breakfast the readings of the Libre and my meter were exactly the same. I took a scan and did a finger prick at around 4:40pm last night before I went out to visit my parents and there was 0.2 mmol/L difference which is perfect. When I tested before bed it was 1.1 mmol/L below my finger prick so I wasn't concerned. This morning before breakfast my Libre was 2 mmol/L below my blood meter (6.8 on Libre, 8.8 on meter). I also noticed on Sunday night/Monday morning it actually stopped recording for a couple of hours between midnight and 2am - even though I took my scans overnight well within the 8 hour window (I'm a light sleeper and wake up many times during the night so when I wake I scan).

Worryingly, it's actually recorded a few instances of hypo, which I know for a fact I didn't have, as I felt fine and my finger pricks agreed with how I was feeling.

I've only been having these issues with the past couple of sensors I have applied - the ones previous have been spot on, so I'm hoping I have just got a couple of bad ones - possibly from the same batch as I got them both at the same time with my last prescription. Will keep trying to spot patterns but so far it seems completely random.

 

[helli]

What are the trend lines like when there is a large difference? You mentioned an issue before breakfast - could you be experiencing Foot On The Floor with your levels rising fast? Sometimes, Libre can take a bit of time to spot a rise.
It is only worthwhile comparing finger pricks with Libre if your levels are "in normal range" and stable.

 

[Lisa66]

Hi @CivicFreak …apologies for late reply.

Today my sensor seems to have been spot on all day. However my levels have been much better today than yesterday, I’ve no idea why. I do, as others have mentioned regarding Libres, notice that they “overshoot” a bit at either end of the range.

Did the hypos actually have the graph line going down? I’ve noticed a couple of times, when it’s predicted that later there’s just a dot hanging in the air, with the graph line more or less where I think it should have been.

I always try and remember that they have a slight time lag to them and aren’t measuring blood.

I also remind myself every now and then, that until 5 years ago I didn’t have any idea what was going on between finger jabs… so unless the readings are wildly out, as with our last sensors, I still find the arrows very helpful.

 

[CivicFreak]

Hi @CivicFreak …apologies for late reply.

Today my sensor seems to have been spot on all day. However my levels have been much better today than yesterday, I’ve no idea why. I do, as others have mentioned regarding Libres, notice that they “overshoot” a bit at either end of the range.

Did the hypos actually have the graph line going down? I’ve noticed a couple of times, when it’s predicted that later there’s just a dot hanging in the air, with the graph line more or less where I think it should have been.

I always try and remember that they have a slight time lag to them and aren’t measuring blood.

I also remind myself every now and then, that until 5 years ago I didn’t have any idea what was going on between finger jabs… so unless the readings are wildly out, as with our last sensors, I still find the arrows very helpful.

Yes the hypos showed the graph going down, and the arrow pointing down as well. Finger prick didn't agree with my sensor reading, so I knew it wasn't right.

Today and last night has been much better though, and seems much closer to my blood results - I'm talking less than 1 mmol/L difference, so I'm happy.

I do always take into account the lag time between the sensor results and the blood results, and if there's a discrepancy I tend to re-scan a few minutes later. Generally I've been pretty confident in the sensor results, but the last 2 have been a bit odd. Could still be a one-off. I applied my current one on Saturday so it's only 4 days in, and this doesn't shake my confidence in the Libre because for the most part they have been more than accurate 🙂