Freestyle libre vs Codefree

[CherryAA]

I've been using the Freestyle for 3 weeks now. Having read other comments I am not expecting total accuracy and it does seem that the freestyle generates lower numbers in general than the codefree ( by maybe na average 0.8 to 1.0 mol) I now see that some people put the sensor in a day early to give the site chance to recover before starting to takee the readings ad that seems to make sense as the first day's readings for me are clearly too low.

However the other thing I have noticed is that my readings are a LOT smoother on the freestyle , for for example this morning - a reading of 7.7 on the freestyle , a reading of 10.3 using codefree strips- then doing another codefree test 15 seconds later codefree then says 8.6. I have often had these big swings on codefree, whereas libre very rarely does something I am not expecting. ie when I do not eat food at all the readings stay pretty consistent for hours on end, with codefree it still often jumps about quite a bit. Intuitively it feels like the freestyle must be giving a better reading during these periods if absolutely nothing else is happening in terms of movement, food or water intake.

i would be interested in others experience of this

 

[Bluetit1802]

Are you waiting around 10 to 15 minutes between using the Codefree and scanning the sensor? There is a time gap because the sensor measures interstitial fluid as opposed to blood, and the interstitial fluid runs behind blood.

 

[steve_p6]

The codefree is giving you instantaeous measures which are only required to be accurate to +/- 10%. The libre uses an algorithm looking at the last (10 I think) 1 minute data samples from the Interstitial Glucose. It uses this to then predict what it thinks your BG is. Most times this will naturally smooth out the consecutive readings when you scan. Occassionally there is a bit of bad data which causes a spike/drop in readings but that will correct within a few minutes.

 

[Brunneria]

I've had a good few sensors over the last year or so.

Often the reading jumps about a bit, but I think there is a good explanation for it.

For example, first thing in the morning, I wake up, move one arm, zap the widget and get a reading of (say) 6.1
Then I lurch to my feet, trundle 20 feet to the bathroom, before returning to bed for just 10 more mins. If I zap again at that point, my bg could be showing 6.6.
Five mins later, it is back to 6.1 again.

This is a fairly consistent thing.

It happens if I have spent hours at my desk, and then nip upstairs to the loo, or if I have been couch potatoing, and decide to scramble around the kitchen throwing a meal together.

Yet these small but rapid rises never show on the graph, although they are visible on the list of scanned readings.

I just assume that firstly, the increased activity very briefly raises glucose levels in my interstitial fluid. Then secondly, that the Libre irons out such jagged short term readings, so smooth out the curve.

 

[leking]

It isn't a perfect science, I'd doubt your summary did a little rise in that scenario. I don't think the figures are literal.

Same when we use a finger prick, if you do three in a row they will all be different usually. It doesn't mean our bg has actually moved each time.

I'm finding the libre to be pretty consistent around the same kind of level as my finger picking would say. I care more about the general area my bg is in than the actual figure.

I think aiming for an area, instead of a figure is a good way to manage things?

 

[CherryAA]

I think my current libre is giving me consistent readings about 1 mol lower than the codefree , though on occasion it goes a bit closer with only about 0.5 difference . Currently the average daily libre readings have been 6.1 to 6.3 which it were true would be lovely ( with the 4 day segments average being 5.7,7.2 ,6.2 and 5.9) I just doubt it somehow,

I have been comparing the codefree and the libre and concluding that the libre was reading too low. Having said that I have just checked the actual finger prick test on the freestyle libre with the sensor reading on the libre and they both give the same result, both 0.5 lower than codefree. (I've not eaten for 4 ours no so the time lag shouldn't really matter much) . I have no clue if there is any good reason why the codefree should be more accurate than the libre if the libre tradiitonal blood test seems to be saying the same thing as the libre sensor.
This sense that either one is consistently reading too low or the other too high has only happened when I fitted my second sensor, but I also got a new tub of codefree strips at the same time so could be either or both !

The codefree is giving you instantaneous measures which are only required to be accurate to +/- 10%. The libre uses an algorithm looking at the last (10 I think) 1 minute data samples from the Interstitial Glucose. It uses this to then predict what it thinks your BG is. Most times this will naturally smooth out the consecutive readings when you scan. Occasionally there is a bit of bad data which causes a spike/drop in readings but that will correct within a few minutes.

thank that helps explain it a bit . I'm even more flummoxxed because I recently did a home hba1c which showed a increase in that measure from 5.9 to 6.6% in the last ten days and that doesn't make much sense either .
I suspect I might be suffering from trying too much!

The one thing that the sensor made clear to me I that I should quit eating before 1pm and after 7 pm and that the later in that window I leave it the more carbs I can get away with . I should probably jut focus on that for now and leave the precise measurements to the professionals !