BACKGROUND: I've been using the libre2 sensor on prescription for well over 2 years now with no issues (apart from two falling off, and one telling me it had malfunctioned a week into it's life). On the rare occasion I have calibrated my sensor with a finger prick it has been usually either spot on or within 0.5, even during periods of transition. Not even the 15-30 minute delay has caused any issues. My Diabetic team at the hospital (UK, been a T1 since the age of 7 and now nearing 30) advised finger pricking isn't really necessary even to calibrate, even when driving as the DVLA accept CGM machines as accurate now, it's only if you are in hypo or exhibit symptoms you must test which has never been the case for me as I get really good warning signs.
My sensor ran our on Friday night, so I replaced with a new one. For the last week my BS readings have improved on normal, especially overnight which I attributed to a change in Glargine.
On Sunday afternoon (yesterday) my Libre was showing me as 3.4. Odd I thought, I felt fine and usually once I go below 4.5 I start to get the feeling of dropping and get a bit sweaty and just general yuck feeling. Anyway, I had some glucose and some carbs and 30 minutes later my Libre was showing as LO... weird, I had a little bit more glucose and then 10 minutes later I was showing as 6.4.
Great, I thought. Here comes the bounce. I decided to test 15 minutes later so I could begin and gauge how much novorapid to microdose through the bounce and it was showing as 4.2.... 5 minutes after that? 3.6 again. At this point I finger pricked to show 11.4. I then decided to monitor over the next 5 hours and do regular finger pricks and Libre readings. I have enclosed these on the image.
In summary, these were off anywhere between approx 2.0 mmol and 11mmol. I removed the sensor, and put a new one on as it was clearly faulty. I even switched arm.
I then did the same with this monitor (but not written and recorded) about 12 hours after starting it and it was anything between 0.1 and 1.5 in difference to a finger prick. No issues with that, seemed the norm. Then this afternoon (just after 24 hours had gone) the same differences as the other Libre started to occur. These are also on the image attached. Please note these readings were only taken during periods of questionable readings from the Libre and purposefully was selective in the amount of insulin given to make sure it wasn't a very big delay being the cause of issue for the ''test'' and my readings are usually nice and settled and lower than the finger prick results!
My sensor then failed and said there was an error and I needed a new one. I also use Glimp every now and then so I've recorded the levels from that, as I was wanting to make sure it wasn't a Libre app issue, or me, or the sensors themselves.
I've contacted Libre who have sent out replacements, but i am perplexed and now have some serious trust issues! The cherry on the cake is I leave for a beach holiday on Friday and whilst I was going to take my finger prick with me, was looking forward to practically hands free monitoring from the poolside! Has anyone ever become immune to Libre sensors?
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UPDATE: The replacement sensors from Abbott have arrived. 2 hours in and I haven't left between 6.0 and 6.8 on my libre app, yet between 4 different finger prints I've ranged betwwn 8.5 - 10.7. Not looking promising. The auto CGM is also turned off for some reason on the app for this sensor and doesn't seem to be on, I will post an updated spreadsheet later with the disparity with this one.
