# Libre reader graphs



## trophywench (Apr 24, 2021)

Why do the graphs not match the scans?  So lots of the little circles float above the graph line in mid air hence the one I had at 11.3 - which did match my BG - is in mid air a couple of hours ago.  I was in the mid 6's before lunch for a few hours but from the graph line it was about halfway between 3 and 5.  There are complete breaks in the line in the early hours some days, though I did scan as I hadn't gone to bed yet on those nights, and the little circle from the scan shows in mid air in the gap either side of it, proving that the sensor is working perfectly OK, not just my word that it was.  I do understand that had I not scanned for 6 hrs prior to the early hours but assumed that once I did scan, the line would re commence fairly soon thereafter, but apparently it doesn't - and it's the same when I download it onto Libreview and look at the graphs on there.


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## barrym (Apr 24, 2021)

There was a very good explanation either here or on co.uk, suggesting that the overall analysis of all readings would make some appear a little odd so it shows the dot but smooths the curve. 

I might even have that close, it's certainly worth looking for the original post.


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## Pattidevans (Apr 24, 2021)

Jen - could you post a screenshot, because I’m having a lot of difficulty visualising what you are saying.  

ps having lots of difficulty not calling you Sedge!


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## everydayupsanddowns (Apr 25, 2021)

It’s because of the way the graph data is sampled.

I can’t remember the numbers exactly, but it’s something like the reader gets a new value every minute, but the graph updates every 5 or 10 with an average of those. And because the algorithm is trying to ‘predict‘ 10 minutes into the future to close the gap between sensor glucose and capillary blood glucose you can occasionally see rogue scans above or below the graph data, especially where your BG does a quick ‘about turn’.

Of course you can get odd scans / sensor values at other times too, and if the sensor gets the feeling that something about the feed of info isn’t right (eg maybe the sensor is coming loose) then it gives the ‘wait 10 minutes’ message until things have settled down - Which will be the gaps in the graph, I think?


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## trophywench (Apr 25, 2021)

I used to take the reader to the bathroom with me last thing at night when I nip in there before I go to bed there's a street light that side of the house which helpfully provides enough light so you can just about see, so when we wake up in the middle of the night to use the loo we don't have to put our light on LOL so I could scan it, but recently I haven't done that - eg last night I plugged the reader into the mains to charge it at bedtime - so think I'll just recommence doing that and see if that closes the gaps up.  Makes sense that if the sensor has just recorded a higher glucose level (rather than it actually being scanned by the reader) but those before and after weren't as high then the graph line won't go exactly through that higher or lower number, of course. 

However - why on earth would anyone's BG do that ! - yeah I know nobody's BG stays exactly level 24/7 blah - but these look like my BG hiccups!    Perhaps everyone's BG does that sometimes ....

Fascinating, innit?

@Pattidevans - abbreviate it to TW ?


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## barrym (Apr 25, 2021)

I think you're overthinking this. I've seen this reasonably often, strangely even yesterday. A single scan which was quite high, and the dot went above the graph line. At the next scan the graph was down to a sensible level and the dot was floating on its own. 

I've also seen where you get a scan reading that doesn't appear in the data you can download from LV. 

All very weird, just best to let them remain life's little mystery .


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## Pattidevans (Apr 25, 2021)

trophywench said:


> I used to take the reader to the bathroom with me last thing at night when I nip in there before I go to bed there's a street light that side of the house which helpfully provides enough light so you can just about see, so when we wake up in the middle of the night to use the loo we don't have to put our light on LOL so I could scan it, but recently I haven't done that - eg last night I plugged the reader into the mains to charge it at bedtime - so think I'll just recommence doing that and see if that closes the gaps up.  Makes sense that if the sensor has just recorded a higher glucose level (rather than it actually being scanned by the reader) but those before and after weren't as high then the graph line won't go exactly through that higher or lower number, of course.
> 
> However - why on earth would anyone's BG do that ! - yeah I know nobody's BG stays exactly level 24/7 blah - but these look like my BG hiccups!    Perhaps everyone's BG does that sometimes ....
> 
> ...


TW... I can get a straight line overnight with judicious adjustments to the pump, but the last 3 days it's drifted down into the just under 3.9 range by morning.  Done another tweak... the weather?  Who knows... perhaps you need to tweak again?


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## trophywench (Apr 25, 2021)

I'm in agreement with @barrym - just part if life's rich pattern - kind of 'just wondering out loud', except in writing! LOL


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