So many lows with Libre 2?

[CathyFP]

Hi,
I’m a recently diagnosed Type 1 and have been managing quite well with my Insulin and Libre CGM but I changed the monitor three days ago and seem to be getting lots of lows. Some of the time when I check these with finger pricks I am not below 4. Are monitors ever faulty? I really feel like I have no idea what is going on and it is starting to make me feel very low.

 

[rebrascora]

What sort of difference are you seeing? Libre always reads lower than my BG meter but usually within 1mmol, sometimes a bit more, but I mostly only double check when my levels are stable. If levels are dropping but you have eaten then Libre will often indicate you have dropped into the red when you haven't due to the algorithm it uses to make up for the lag between blood and interstitial fluid glucose which is what the sensor reads. So if it shows your levels dropping fast but you have eaten carbs, it will take about half an hour to realise that levels have stopped dropping and gone back up but in that half hour it will often show you in the red ie. under 4 but sometimes when you look at the daily graph it doesn't show you having been in the red.
Also, if you lie on the arm with the sensor in your sleep, the pressure will cause what we call a "compression low" Again, it will usually take 20-30 mins after you release the pressure for it to record your correct glucose level. If it is consistently reading more than 2mmols low then you can report it to Abbott and they will usually send a replacement, but they like 3 comparative finger prick readings showing a significant difference. If they are compression lows from lying on the sensor at night, then you can usually find a placement on the arm where it doesn't happen or learn not to lie on the arm with the sensor, in a similar way that you learn not to roll out of bed.

 

[Bruce Stephens]

Are monitors ever faulty?

It's not that uncommon.

 

[Tdm]

It's not that uncommon.

Sometimes peoples bodies don't get on with a particular sensor...if libre diesn't work well for you, you can ask for dexcom one.
Alternatively there is 3rd party software that will allow you to calibrate your raw libre data

 

[CathyFP]

Sometimes peoples bodies don't get on with a particular sensor...if libre diesn't work well for you, you can ask for dexcom one.
Alternatively there is 3rd party software that will allow you to calibrate your raw libre data

Thanks I’d like to know more about this software.

 

[Alexafam]

I have had a few sensors over the years that have been faulty. if you give them a call, they will send a replacement and an envelope to send the faulty one back. i would just change it now if you are concerned.

 

[Proud to be erratic]

Hello @CathyFP, while it might seem great to be able to calibrate your sensor, this is a procedure that should be done sparingly. Unless you are in a very steady (level) state with no or minimal insulin on board, been inactive not just for a while but also carrying no extra activity from the day before which can "kick in" when it's least expected, etc .... the CGM algorithm (that's doing its best to compensate for the natural lag between interstitial and actual BG) gets confused and puts you into its own sort of roller coaster effect by over or under calibrating. Do this a couple of times and your readings get further adrift rather than in harmony and then the sensor just "surrenders".

Abbott were extremely good about replacing every single reported failure for me. But I found the constant fails and the reporting process was not just adding to my stress from never being sure, but also just having to jump through hoops as part of the failure reporting process. It all added to the inevitable intrusion of my D. I am someone who initially felt that Libre 2 was barely fit for purpose, and who gradually came to accept that my body and Libre 2 simply weren't great friends! For about a year I persevered and worked with poor correlations for the most part, but I was finding the trend arrows were reliable. From this mindset I stopped worrying about the exact reading if it was showing somewhere mid range. Indeed I still blatantly ignore the decimal point and round up or down to the nearest whole number - because the reality is that is as accurate as the tech really is; adding a decimal point with a figure afterwards might make great marketing, but is not that true.

I saw my Libre readings through the unofficial Diabox app, which did allow me to calibrate Libre 2 (I think Diabox have now discontinued that option) and so had 1st hand experience of being able to calibrate.

I was eventually able to change to Dexcom One which was a bit more reliable, but still not brilliant and eventually I resorted to self-funding Dexcom G7; that proved to be excellent. Suddenly a load of stress was removed. By proving that there was actually a CGM that was compatible with me, my Consultant made a case for the Hospital to fund G7 and I no longer have to self-fund. G7 can be calibrated; I rarely need to do that and when I do need to, I only need one calibration to get back on track.

 

[Bruce Stephens]

I saw my Libre readings through the unofficial Diabox app, which did allow me to calibrate Libre 2 (I think Diabox have now discontinued that option) and so had 1st hand experience of being able to calibrate.

The author of Juggluco (an unapproved Libre app) has resisted adding calibration on the grounds that the sensors have such a limited useful range that calibration doesn't (he feels) make much sense.