Free style libre issue

[AbiParkin]

Hi,

I’ve only had T1 since May but recently three out of four of my sensors have been faulty and giving me extremely low readings when my sugar is actually on the high side of normal.

It’s causing me a lot of stress especially now I’m away on holiday and just changed to a new sensors, which seems to be having the same issue. Is this something anyone else is encountering and what do you do?

 

[helli]

Are you aware of the limitations of Libre?
For example, if you have only just applied your sensor in the last 48 hours, it may not have “bedded in” and your body is getting used to the alien object in your arm which is resulting in inaccurate readings.

 

[everydayupsanddowns]

Sorry to hear some of your sensors haven’t lived up to your expectations @AbiParkin

Sometimes it can take a day or two for a sensor to settle. The first 24 hours in particular was always a bit dodgy, certainly in Libre1.

Some members find that inserting a sensor 12 hours or more before activating it seems to give better results (though Abbott don’t recommend this).

Are you reporting these sensors to Abbott. They can troubleshoot the insertion process, and will be able to check lot numbers if you are not the only one having problems.

Hope your current sensor settles soon.

 

[rebrascora]

As @helli says, Libre has quirks and limitations. So whilst you may have faulty sensors it may also be a lack of understanding of how they work. For instance, another issue with them is that if you apply pressure to the Libre sensor by lying on it for instance it causes what we refer to as a compression low, so the alarm may go off in the night to say you are low if you lie on it, but a finger prick will show your true reading. Over time you either learn to place it where this won't happen, or you learn not to lie on it.
Also, because it measures interstitial fluid rather than blood and interstitial fluid lags behind blood glucose by about 15mins, the algorithm in the app tries to predict what the reading will be in 15 mins from the time you scan it. It does this by extrapolating from the sensors previous readings, but if levels are changing fast or suddenly change direction because you have injected insulin or eaten fast acting carbs, that prediction can be significantly wrong, so it is important to take that into consideration when you test and is one of the main reasons why you should not rely on Libre to check that you have recovered after treating a hypo, because it will usually show you as going lower when a finger prick will show you coming back up.
All that said, some people have had significant problems with Libre sensors and perhaps some people's bodies are just not suited to them, but I think there are also software issues which cause a lot of problems rather than the sensors themselves being faulty. Knowing the limitations of the system is important to assess where the problem may lie.

I find that Libre usually reads about 1mmol lower than finger pricks when my levels are nice and stable and in range. I have had the odd sensor which has read 2mmols lower and if that is consistent, I can work with it. If it consistently reads more than 2mmols below (or above) finger prick levels when I am comparing like for like.... ie when levels are stable, then I report it to Abbott who are very good at replacing them. They usually require 3 readings where Libre and finger prick BG were significantly different so do make sure to collate that information before you ditch the sensor.

Also, just to reassure you that many people survived with diabetes long before finger prick tests were available let alone Libre, so whilst the technology is good, do learn to listen to your body rather than rely on it or feel that you can't manage without it.