Libre 2 consistently 2.5 mmol/L low.

[LittleGreyCat]

I thought I was acing it, keeping in the green.
So I experimented a bit and seemed to cope with more carbs remarkably well.
Having been assaulted by the Too Good to be True Fairy a few times in the past I started finger pricking and it turned out the sensor was reading 2.4 to 2.5 mmol/L low consistently.

Sigh.

I've turned off the low BG alarm and am hitting around 3.5 when I try hard.
Turns out an inaccurate Libre 2 can still be useful if you cross check.

Only a few days left, then I start a new one.
Let us see how good that is.

I won't be believing the estimated HbA1c though.

 

[Rokaab]

Only a few days left, then I start a new one.
Let us see how good that is.

You can get Abbott to send you a replacement if its a long way out btw, they can just not work properly (same as any tech)

 

[jackois]

Are you allowing for the ten minute lag between actual blood sugar when you test with the fingerprick and the Libre, which uses interstitial fluid to measure?

I've found, you should test finger, see what the reading on the Libre is ten minutes or so later to be properly accurate.

 

[Deleted member 527103]

Are you allowing for the ten minute lag between actual blood sugar when you test with the fingerprick and the Libre, which uses interstitial fluid to measure?

I've found, you should test finger, see what the reading on the Libre is ten minutes or so later to be properly accurate.

The algorithm used for Libre 2 to convert Interstitial Fluid Readings into Blood Sugar Readings takes into consideration the 10 minute lag so, unless your levels are changing direction, you should not have to allow for the lag yourself.

 

[EllieM]

I am puzzled as to why the libre don't allow user calibration. My dexcom occasionally reads high or low, but after calibration it's almost always fine ....

Certainly you'd think that a consistent high or low reading would be fixed by calibration.

 

[jackois]

The algorithm used for Libre 2 to convert Interstitial Fluid Readings into Blood Sugar Readings takes into consideration the 10 minute lag so, unless your levels are changing direction, you should not have to allow for the lag yourself.

Apologies, my bad.

I had to stop using Libre before the Libre 2 due to skin issues and didn't realise that this was a featrue. Currently using Dexcom G6.

 

[Antje77]

I've turned off the low BG alarm and am hitting around 3.5 when I try hard.
Turns out an inaccurate Libre 2 can still be useful if you cross check.

My sensors have almost all read between 0.8 and 2.0 mmol/l lower than a fingerprick, for years.
Like you said, this makes the low alarm useless.
As for my hba1c so far (over 5 years) it has always been 8 mmol/mol higher than the predicted one for me, so I'm pretty sure I know what my hba1c is now based on my data. Mind, this is not the same for everyone, for some theLibre is usually spot on, for some Libre reads higher than blood and for some it reads consistently low.

Now I use DiaBox alongside the official Libre app, it has a wider range of alarm levels and more important, you can calibrate it!
It also sends your numbers from the Libre2 directly to your phone without the need for scanning. I still scan with the official Libre app to get all data though, I like the different graphs even if I have to mentally calibrate them.

If you want to try it, you can download it from here, although I think it still only works on android, not iPhone: https://sirius.thetaphi.de/diabox/?...91zIYxpLT81If4sSzjNETDsUrpMdl4THcwpS29ZgyscOo
It does help a lot if you join their Facebook group for information and problem solving: https://www.facebook.com/groups/974278412920319