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Freestyle Libre Arrows Inaccurate?

J

Jelaca

Well-Known Member
Messages
225
Location
UK
Type of diabetes
Type 1
Treatment type
Insulin
Hi all,
I got my first freestyle libre sensor about 6 days ago and have been happy with it. I did notice that the direction arrows to show where your sugars may be heading seem quite inaccurate though. Has anyone else found this?
For example, I tested 10.1 and it said I was going rapidly down but then I retested about 10 mins later and it was actually 10.5. It’s hard to trust the arrows if this happens.
I’m wondering if it’s maybe because I’ve not had it a full week yet so could it still be adjusting? Or have others of you noticed this too?

Thanks so much,
Jessica
 
New sensors need a short while to bed in before they give reliable results. I do not use one so this is what I have seen as reported by others. Also, any kind of trend analysis (fortune-telling) takes a while to come to a viable conclusion and will need several results to work on.
 
The Trend Arrows will always have a degree of inaccuracy which makes perfect sense based on how it works.

Why?

Your Libre both doesn't know when you took Insulin or when it will begin acting. It also doesn't know when you eat food and when it'll begin having an effect on your blood sugar. Likewise, it won't know when you're exercising and for how long etc etc. The Trend Arrows merely suggest "if following the current trend, this is what should happen."
 

Hi,

The arrow direction for me, pretty much shows where I came from & the the possibility of where I'm heading regarding insulin on board & or what was eaten.
I tend not to go on such a short linear timescale (like 10 minutes?) with the case of something like a correction dose, I personally look for some sort of turn around in about an hour. (Or just after.). & hopefully a continued level out after 3h..? (Keeping a look out for a little trick at the 5th hour with my Novorapid deciding it may drop me further?)
 
Yeh I find they can be quite inaccurate so I don’t rely on them. If I’m going to do anything I always double check with a finger prick, it’s the only way to be 100% sure.
 
The arrows tend to look back quite a long way.
If you look at the graph and see a steep downward or upward slope over (a guess) 30 minutes or more then the trend arrows are reasonable.

With the Libre 2 the software seems to play its cards close to the chest for a while, and is prepared to ignore out of trend readings.
I've had false hypo warnings when sleeping on the sensor which then disappear from the daily graph because of the instant rebound.
 
I ignore the arrows but look at the trends on the graph and add my knowledge of when I last ate and dosed.
I find the arrows only consider the last one or two readings and my readings can bounce around a bit so they do not consider trends.

It is another example where the data from Libre is only useful if you know how to convert the data into useful information. You still need to think.
 
I've been using Libre 2 for 6 weeks and I just ignore the arrows as I find them pretty useless. I just take a reading more frequently if I'm worried about where I am.
 
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