Sensor error – repeat accuracy

[rebrascora]

I must admit my arm isn't ideal for me because when I am working hard outside (or running) in a vest or crop top at this time of year, it gets cold easily and refuses to give a reading... A few weeks ago it got cold on my arm under a fleece one night when I was out walking even though my body was perfectly comfortable temperature wise. It was just the surface skin on my arms which was cold.... and it wasn't sub zero or anything at the time. My torso is always warmer than the exterior of my arms, so I could see it as helpful in that respect too although for ladies like myself, finding a place where a bra or sports top was not going to catch on it might be a little more challenging than for a man.
I had a 15 min gap on my graph the other day because I went out for a run and it wasn't covered and got too cold to work!

 

[Paulbreen]

I must admit my arm isn't ideal for me because when I am working hard outside (or running) in a vest or crop top at this time of year, it gets cold easily and refuses to give a reading... A few weeks ago it got cold on my arm under a fleece one night when I was out walking even though my body was perfectly comfortable temperature wise. It was just the surface skin on my arms which was cold.... and it wasn't sub zero or anything at the time. My torso is always warmer than the exterior of my arms, so I could see it as helpful in that respect too although for ladies like myself, finding a place where a bra or sports top was not going to catch on it might be a little more challenging than for a man.
I had a 15 min gap on my graph the other day because I went out for a run and it wasn't covered and got too cold to work!

Hi Barbara take a look for “type one talks” on YouTube he has a video for his top 5 sites for sensors, none of them on the arm by the way

 

[Fagor]

I find it very difficult to not follow the advice given (except when I mis-understand it which seems to happen more often now). Abbott did ask specifically whether I followed application instructions as one of the questions.
Seen a YouTube where user tested it on various locations, but can't remember site, but might try again if you're interested.

New sensor is fine, todays BGs all between 4.6 and 7.2, and highest in last 7 days 10.8. Libre really seems to make a difference.

 

[rebrascora]

I find it very difficult to not follow the advice given

I am like that but since I did a bit of research and went against the low fat advice I was given when I was diagnosed and have found that exactly the opposite works better ie a low carb, high fat diet suits me far more and I am slimmer and fitter and more full of energy than I have been for 30 years, I am becoming a little more adventurous about exploring and experimenting beyond the advice in other fields... particularly when the current advice is not always suiting my purpose ie sensors not working in the cold or getting caught on clothing and pulling off after a run.

@Paulbreen Thanks ... will have a look at that on YouTube

 

[everydayupsanddowns]

I use a "watch strap" thingy for extra protection and it's towards the inside of my arm to avoid doorways attacking it.
I only use the Libre reader, as my smart phone isn't very smart.

Be a bit careful about those elasticated things that are supposed to help. Glucose sensors aren’t supposed to be ‘pressed in’ to the skin with downward pressure - this can inhibit the circulation of the interstitial fluid that the sensor is reading and reduce sensor accuracy.

I’ve rarely needed to use anything to keep a Libre in place for the 2 weeks, the problem seems to be in prising them off at the end!

 

[everydayupsanddowns]

They won’t know that you haven’t put the sensor in your arm unless you tell them though, will they!
No reason why you shouldn’t be able to put them anywhere else, it just hasn’t been tested.
Having said that though, we always found they worked perfectly well on the arms and never put them anywhere else.

I don’t think that’s strictly true. There is trial evidence for Libre which shows lower accuracy on other sites for the (small) trial population.

85.5% of results falling in a good ‘error grid’ zone for the arm, vs only 64% when Libre worn in the abdomen (and 98% for Libre reader fingersticks)

Performance of the FreeStyle Libre Flash glucose monitoring system in patients with type 1 and 2 diabetes mellitus

Objective To evaluate the performance of the FreeStyle Libre Flash continuous glucose monitoring (FSL-CGM) system against established central laboratory methods.Research design and methods 20 subjects (8 type 1 diabetes mellitus, 12 type 2 diabetes mellitus) were analyzed. FSL-CGM sensor...

drc.bmj.com

 

[grovesy]

I don’t think that’s strictly true. There is trial evidence for Libre which shows lower accuracy on other sites for the (small) trial population.

85.5% of results falling in a good ‘error grid’ zone for the arm, vs only 64% when Libre worn in the abdomen (and 98% for Libre reader fingersticks)

Performance of the FreeStyle Libre Flash glucose monitoring system in patients with type 1 and 2 diabetes mellitus

Objective To evaluate the performance of the FreeStyle Libre Flash continuous glucose monitoring (FSL-CGM) system against established central laboratory methods.Research design and methods 20 subjects (8 type 1 diabetes mellitus, 12 type 2 diabetes mellitus) were analyzed. FSL-CGM sensor...

drc.bmj.com

That is what I understood too.

 

[rebrascora]

Peoples bodies all respond differently and a new unapproved site might be beneficial for one person but not another. The fact that we can double check readings against finger pricks to gain confidence in a new site or reject it is an important factor if you do decide to experiment, as well as taking into consideration that Abbott may not support potential failure of a sensor in an unapproved location. The high cost (or limited provision via the NHS) of the sensors means that experimenting is a tad risky. I guess you have to weigh up potential gain against risk. Most people probably don't have any problem wit wearing it on their arm so no need to try anything else. I am having a few minor issues so it is making me consider experimenting.

 

[Fagor]

I use my strap as a form of comfort strap, as it's not very tight unsure how effective it is.

I used baby oil on the adhesive and sensor came off easier than first, but two tests isn't very rigourous.

 

[danielmg]

I've just had my first 'sensor error - check again in 10 minutes' message on the libre reader. Checked the sensor itself and doesn't appear to be dislodged or damaged at all, and not done anything differently in my routine to cause this. Would it be wise to contact Abbott or see if this repeats? Also, has anyone found using an adhesive over the sensor to have helped with this error?

 

[Robin]

I've just had my first 'sensor error - check again in 10 minutes' message on the libre reader. Checked the sensor itself and doesn't appear to be dislodged or damaged at all, and not done anything differently in my routine to cause this. Would it be wise to contact Abbott or see if this repeats? Also, has anyone found using an adhesive over the sensor to have helped with this error?

I had one of those messages the other day. It was when my BG was rising fast after some Christmas excess, but was just hitting the peak before falling again, and I think the sensor sometimes gets confused when levels are changing rapidly. It has an inbuilt algorithm to try and narrow the time lag between a Libre reading and a finger prick, and sometimes it can’t cope when things are changing direction fast. Ten minutes later it worked fine, and continued working well up to the end.

 

[danielmg]

I had one of those messages the other day. It was when my BG was rising fast after some Christmas excess, but was just hitting the peak before falling again, and I think the sensor sometimes gets confused when levels are changing rapidly. It has an inbuilt algorithm to try and narrow the time lag between a Libre reading and a finger prick, and sometimes it can’t cope when things are changing direction fast. Ten minutes later it worked fine, and continued working well up to the end.

Thank you for your reply @Robin. Strangely, I had some weird readings overnight. I've attached the trend graph here. Normally my glucose is consistently low (still trying to figure that out), but it seemed to rapidly rise and fall, with data missing either side for some reason. I then got the sensor error earlier today, so I wonder whether this is a coincidence or related.

 

[rebrascora]

@danielmg
That trace is odd. Could you have been lying on the sensor. Usually that will cause a compression low but I appreciate you have been having problems with lows for a while so I am not suggesting the red incursions are compression lows but just wondering if you have been lying at a funny angle on the sensor and it hasn't liked it for some reason. I would probably be more likely to ring Abbott about those weird overnight results than a one off sensor error... try again later message... but obviously if it starts happening more frequently then it suggests there is a problem.
Out of curiosity how long has this sensor been in use?
As regards covering it with a dressing, I believe the official Abbott guidance is not to but many people do. Tegaderm is the most frequently recommended dressing and many people cut a small hole in the centre to allow the breath hole in the sensor to vent. Cutiderm are another similar dressing. You can also get dressings that have been specifically designed to go over the sensor and come in various designs if you want to bling your sensor. Personally I find Micropore works fine for me. I cut 3 lengths about 3 inches long and form a triangle with them over the edges of the sensor leaving the centre hole uncovered. I tend to use the sensor for a week uncovered and then tape it down after that as I have twice had problems with it coming off on day 8 after a hot shower and once on day 12. Abbott have been good about replacing them but it is less inconvenient to tape and prevent any possible problems. With the extra tape for the second week of it's life it holds much better for me and it is peace of mind to enjoy my hot shower.
Hope your sensor settles down but if not, give Abbott a ring. Their customer services are very good.

 

[Robin]

Thank you for your reply @Robin. Strangely, I had some weird readings overnight. I've attached the trend graph here. Normally my glucose is consistently low (still trying to figure that out), but it seemed to rapidly rise and fall, with data missing either side for some reason. I then got the sensor error earlier today, so I wonder whether this is a coincidence or related.

I wonder if your BG levels were rising, but you lay on the sensor and compressed it, causing it to register a low reading. It sometimes happens with me, that I get a dip into the red and back out again, and it’s because I’ve compressed the sensor when lying on it. So your sensor would be getting the message that your BG was rising and falling rapidly, and it couldn’t cope.
Edit: @rebrascora types faster than I do!

 

[danielmg]

@danielmg
That trace is odd. Could you have been lying on the sensor. Usually that will cause a compression low but I appreciate you have been having problems with lows for a while so I am not suggesting the red incursions are compression lows but just wondering if you have been lying at a funny angle on the sensor and it hasn't liked it for some reason. I would probably be more likely to ring Abbott about those weird overnight results than a one off sensor error... try again later message... but obviously if it starts happening more frequently then it suggests there is a problem.
Out of curiosity how long has this sensor been in use?
As regards covering it with a dressing, I believe the official Abbott guidance is not to but many people do. Tegaderm is the most frequently recommended dressing and many people cut a small hole in the centre to allow the breath hole in the sensor to vent. Cutiderm are another similar dressing. You can also get dressings that have been specifically designed to go over the sensor and come in various designs if you want to bling your sensor. Personally I find Micropore works fine for me. I cut 3 lengths about 3 inches long and form a triangle with them over the edges of the sensor leaving the centre hole uncovered. I tend to use the sensor for a week uncovered and then tape it down after that as I have twice had problems with it coming off on day 8 after a hot shower and once on day 12. Abbott have been good about replacing them but it is less inconvenient to tape and prevent any possible problems. With the extra tape for the second week of it's life it holds much better for me and it is peace of mind to enjoy my hot shower.
Hope your sensor settles down but if not, give Abbott a ring. Their customer services are very good.

Thank you, Barbara. The sensor is fairly new; been in use about 4 days now. It is sometimes a little painful when I sleep on my left side, as the back of my arm must be pressed into the mattress. I do try to avoid this where possible, however (although not always possible when asleep I appreciate). Strangely just had a new error message on my reader - simply 'LO' (in large letters where the glucose reading would normally appear) + another 'sensor error' message.
I don't know if Abbott are available to contact today with it being a bank holiday, but at least I have BG meter to fall back on in the meantime.

 

[rebrascora]

That sounds to me like the filament may have become dislodged or disturbed and you may find it stops reading altogether soon. You can try the Abbott helpline.... they have out sourced abroad at the moment, so it may not be a bank holiday in whichever country that is. No harm in trying today, but definitely get in touch tomorrow if you don't have success today. They may ask you to go into the menu and give them the error codes and they may well want the sensor back, but they will talk you through the whole process. Don't remove it until you speak to them. They will also want the serial number, so have that info handy if you can.
You should always ensure you have plenty of test strips and a meter even when using Libre. I rarely use a finger prick more than once a day because the Libre has always been very reliable for me and often don't finger prick at all but if you have a sensor failure and no back up sensor to apply until you get the replacement, you can eat your way through a lot of test strips until the new one turns up, even though Abbott are usually pretty speedy in dispatching replacements.

 

[danielmg]

That sounds to me like the filament may have become dislodged or disturbed and you may find it stops reading altogether soon. You can try the Abbott helpline.... they have out sourced abroad at the moment, so it may not be a bank holiday in whichever country that is. No harm in trying today, but definitely get in touch tomorrow if you don't have success today. They may ask you to go into the menu and give them the error codes and they may well want the sensor back, but they will talk you through the whole process. Don't remove it until you speak to them. They will also want the serial number, so have that info handy if you can.
You should always ensure you have plenty of test strips and a meter even when using Libre. I rarely use a finger prick more than once a day because the Libre has always been very reliable for me and often don't finger prick at all but if you have a sensor failure and no back up sensor to apply until you get the replacement, you can eat your way through a lot of test strips until the new one turns up, even though Abbott are usually pretty speedy in dispatching replacements.

Thank you for this advice. Yes there appears to be an event log in the reader with the error codes in chronological order, which is helpful. I did a reader test as well just to rule out issues with that, and it appears to have passed.

I'll try and contact Abbott now and see If anybody can help with this. Luckily I re-ordered the libre sensors on my prescription, which I'll hopefully pick up tomorrow, along with some further BG test strips.

EDIT: No answer unfortunately at Abbott. I'll try tomorrow instead.

 

[Fagor]

I contacted Abbott as my second sensor had several of these errors, 1 or 2 per day from first use, and they sent a new one.
New sensor showed one error after about a week. If that's the only one, I'll just continue with it.

So now my actions would depend on when errors started and frequency.

Can't advise on adhesive, but read somewhere to make sure centre of sensor is not blocked. I use a strap but unsure if I really need it.

 

[danielmg]

I contacted Abbott as my second sensor had several of these errors, 1 or 2 per day from first use, and they sent a new one.
New sensor showed one error after about a week. If that's the only one, I'll just continue with it.

So now my actions would depend on when errors started and frequency.

Can't advise on adhesive, but read somewhere to make sure centre of sensor is not blocked. I use a strap but unsure if I really need it.

Thank you @Fagor. Today is the first time (after using for a few months) I've had any of the errors - and having 2/3 different error codes certainly isn't a good sign.

I wonder if it is possible to have 1 or 2 adhesives added to a repeat prescription to reduce the possibility of errors in the future? Like you said though, It may not be entirely necessary, but I don't see how it could do any harm if not blocking the sensor signal.

 

[rebrascora]

I would be surprised if you would get them on prescription when Abbott don't recommend using them.
I am also of the opinion that if you need over the counter stuff you should get it yourself rather than put extra strain on limited NHS funding.... but that is just my thoughts for my own situation. I appreciate that some people will be struggling to fund even basics so it is up to the individual to decide what they need the NHS to provide for them and then their GP/nurse to decide if they agree.