So, I have vaguely posted about this issue before in other threads about the Libre, but I wanted to post about it here in more detail just to get a little insight from users going through a similar problem.
For context, I’m a former user of the Libre 2 sensors, recently switched to the Libre 2 Plus sensors by my GP in light of the discontinuation of the former. I’m also a user of the Accu Chek Aviva Expert meter, which I’ve had for six years now. Since the end of 2024, I noticed that the difference between my Libre 2 sensor readings and my meter readings tends to get worse. In the first seven days or so, the difference stays consistently within 2mmol for each of my meals and before bed, with the occasional odd difference here and there depending on my blood sugars’ behaviour. But usually, the line of the graph follows closely with the rises and the falls. However, within the latter days of its life, the sensor readings (presumably due to frequent usage) start to stray away from the meter readings, going up to 3 to 4mmol lower than my meter and failing to catch up properly after 15 minutes. I thought that upon switching to the Libre 2 Plus this might resolve the problem, but the same thing has been happening. There have been times where the sensors have started doing this earlier or later than 8 days, sometimes as early as two or as late as four, but most of the time it’s around halfway. Within this year alone, only one sensor made it the full lifespan without any issues. The rest I‘ve ended up changing after about a week.
The frustrating thing is, the sensors aren’t faulty in the sense that they stop working entirely or I have constant connection issues with Bluetooth. In the beginning, they work great. They just cause false readings, rises and drops after a certain amount of time has passed. Which is aggravating for me, as I’m Type 1 and use the Libre to monitor the behaviour of my food and insulin, so it is making my treatment decisions very difficult when I can’t actually tell how high or low my levels are going on certain days. I wouldn’t mind the variations so much if the sensor did correct itself or it was only the odd false reading at certain times, like, after eating or something. But it’s very disrupting having to constantly finger prick because my sensor is reporting false hypos or incorrectly claiming my levels aren’t rising or falling when they actually are, outside of messing up my data on the app as a whole.
Has anyone else experienced this problem and has any tips on how to improve it? I’ve tried putting my sensors on a couple of days earlier to see if that helps, but it’s only good in setting my readings straight within the first 48 hours. I’ve also stopped scanning unless it’s to correct signal loss, which doesn’t seem to help either. And as far as my meter goes, I do frequent control solution tests, so the meter itself and the test strips I use are good.
Is it possible it’s not a sensor issue and I’m just not reacting well to the sensors as a whole? I know some people‘s experiences with CGMs can vary, but they seem to work fine at first.
Could it be the placement of the sensors? I do move them to different spots on my upper arms but it doesn’t seem to matter.
Maybe it’s the time I activate the sensors? I usually try to do it between 4pm and 4:30pm, around an hour and a half to two hours after my lunch.
Any advice or suggestions are appreciated