Libre 2 and finger pricking

[Scaleyback]

Good day all

I have been using a Libre 2 for about 6 weeks, things are going well, one mid morning I tested and it was 3.2, and i wasn't feeling hypo effects, I tried pricking my finger and my bloods were about 15, I took a couple of dextrose and went for a walk with the dogs, came back and libre 2 showed a reading of 2.9 and pricking my finger was 14.2.

Is tend to think it is the Libre, is there anyway of syncing the Libre to make sure it is right please?

Many thanks Mike

 

[Bruce Stephens]

Is tend to think it is the Libre, is there anyway of syncing the Libre to make sure it is right please?

Sometimes they're just wrong. Perhaps a manufacturing fault or perhaps the insertion didn't go right somehow (the filament got bent awkwardly or something). If you report it to Abbott they should send a replacement.

Sometimes they're just a little bit out, or out for the first few hours or something. Whatever the case, if the reading doesn't match how you feel it's worth double checking with test strips (as you did).

 

[rebrascora]

How long have you been using this particular sensor? If it is consistently giving low results, then it is likely a sensor issue and often this will be because the filament kinked during the application process or the sensor adhesive has come a bit loose and the sensor has lifted a bit and then the filament got kinked. Once a sensor is kinked it will usually continue to read low until it advises you to change the sensor. Abbott should replace sensors which are not functioning correctly. They will usually ask for 3 corroborating finger prick readings where it is more than 2mmols out, which clearly yours is way more than that out.
Do you know why your levels are so high?
Just to clarify, providing your fingers are clean and dry and free from any contamination (even the dried juice from chopping onions can compromise it as I found from personal experience) then the finger prick is considered the most reliable result between that and the Libre, particularly if a second test strip agrees more or less with the first as obviously yours has done.

 

[Inka]

Sounds like a dodgy sensor @Scaleyback If you’ve washed your hands and done the fingerprick right, then that will be your correct blood sugar not the Libre.

No, you can’t calibrate Libres. Contact Abbot and report the sensor.

 

[helli]

is there anyway of syncing the Libre to make sure it is right please?

Whilst the official LibreLink app does not allow you to calibrate, there are unofficial apps like xDrip, Shuggah, Diabox and Juggluco which do allow it.
This apps are unofficial so not necessarily available from the App Store. They require some techie knowledge to install and configure but some people prefer them.

However, there are guidelines for calibrating and do so when the readings are so far out (and high or low) is likely to confuse the algorithm.

In this case, I think calibrating is a lost cause. If your fingers are clean, the finger prick is correct and the sensor is defective. If you contact Abbott, they are likely to replace it.

 

[Tdm]

You say you thought yourself in the 3s, ie hypo, which is why you took some glucose, but then went for a walk without checking your sugars were back to normal?

Sorry, but that's not a good idea.

Excercise brings blood sugar down, and you very much don't want to do that if you are already hypo. You need to stop the exercise until sugars back to normal. Even if that means standing like a prat in the rain (been there, done that)

Sorry to be blunt, and perhaps i misunderstood your post, but had to say something.

 

[Bruce Stephens]

Whilst the official LibreLink app does not allow you to calibrate, there are unofficial apps like xDrip, Shuggah, Diabox and Juggluco which do allow it.

Some apps do allow calibration, but Juggluco isn't one of them. (It has many other features, but deliberately doesn't allow calibration.)

 

[Proud to be erratic]

Whilst the official LibreLink app does not allow you to calibrate, there are unofficial apps like xDrip, Shuggah, Diabox and Juggluco which do allow it.

And when I used Diabox a month ago I noticed that it no longer provided calibration. I didn't research if that was now correct; I needed to temporarily use a Libre 2 sensor while in France and without access to decent wi-fi. But several months ago D'box was providing calibration.

 

[Scaleyback]

Many thanks for all your positive feedback, I have contacted my diabetic nurse and awaiting a call back. I think I am going to go back to my finger pricking.

Thank you again 🙂🙂

 

[SimonP]

However, there are guidelines for calibrating and do so when the readings are so far out (and high or low) is likely to confuse the algorithm.

It's not that it confuses the algorithm per se, but XDrip+, for example, will not allow calibrations that are so far out that at minimum sensor raw value the converted blood glucose value is above the hypo level - I think this is actually hard coded with a limit to the range of allowable gradient and intercept values of the calibration line (rather than using the alarm value that is set), but basically it's avoiding the case of having a calibration line that is so far off that it would never tell you that you're hypo.

In the case of broken sensors such as yours, the sensor can never tell you you're hypo as it goes off-scale low before this point, but the XDrip+ calibration fit is not really meant to deal with this, and is trying to avoid accidental fits to the occasional erroneous data points one sees even with otherwise good sensors.

I find that there is enough latitude that I can keep using a sensor with a fairly large offset (the calibration can still cover this), where otherwise I'd have to remove it and get it replaced immediately, however, once a sensor starts exhibiting a large offset it tends to continue to get worse. At least seeing the calibration equation/line moving wrt the previous calibration points gives a pretty strong hint that the sensor is going bad.