# Libre (2) inaccuracies



## Spozkins (May 19, 2021)

Hi  all 

As the title says, I am just curious to know your opinions on course of action when your sensor isn't quite accurate enough. 

So, to clarify, I know there will always be a lag and a slight difference to the fingerprick  test anyway.  I also understand that for the first few days and the last, the sensor is likely to be less accurate as well as when BG is out of range or rapidly changing. But all of this considered WHEN do you decide to contact abbot?  

If you have contacted Abbott what kind of differences where there in your sensor/blood test readings?


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## SB2015 (May 19, 2021)

Hi @Spozkins you have picked up the main issues around discrepancies.
certainly where leveks are changing rapidly these are more evident.

I contacted Abbott if the discrepancies were there over a couple of days.  If in doubt I recorded BG and matching sensor values prior to meals where I would expect things to be more stable.  I avoided times when I had been doing exercise, or had just eaten when things are more likely to be changing more quickly.

When I contacted Abbott they seem to have a set of questions that they go through, including where you position your sensor to check that it matches their advice.


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## nonethewiser (May 19, 2021)

Sure that inaccuracy in first last few days is not applicable now, in early days of libre yes but never noticed it for long time, more so with 2 version.

I'd only report sensor if consistently out with bg readings after taking all other factors into consideration.


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## Spozkins (May 19, 2021)

Thanks guys - but for you how large would the discrepancy be in order for you to contact them?

I'm possibly noticing it more with my current sensor because the alarms are driving me crazy. I could turn them off but it defeats the point really doesn't it?  However, I'm not sure that the difference is great enough for Abbott to be concerned.  I've not contacted them before so don't really have a good frame of  reference.


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## trophywench (May 19, 2021)

Well I know re Libre 1 Abbot did not appear to offer to replace sensors unless the difference was 2-ish.  I haven't had that trouble with the L2 at all really - it's generally more accurate, except below 4.0.  Trouble is, that low an 0.3 difference is actually massive.  Between 4 and 10, NP.  Above 10 well sometimes a difference but usually small by about the same as the low ones, but then the difference between eg 13.8 or 13.5 is pretty immaterial really.

I don't rely on Libre readings at mealtimes.  However, when snacking (say a Digestive biscuit 10g or a scone 35g, 10g would increase my BG by 3.0 so should I bolus for it or not?) If Libre says I'm already over 7.0 cos lunch occurred a couple of hours ago then yeah I'll lob 1u / 3.5u in, without testing BG.  Meter knows what my pump has delivered since 'pre lunch' so when I test pre dinner, it will do the IOB and dinner bolus/correction calc then anyway.


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## everydayupsanddowns (May 24, 2021)

I generally get a feel for whether it’s going to be a good sensor in the first 3-4 days. I have had dodgy ones that came good for their 2nd week after a less-than-ideal first 7 days, but some others that never come into line. I’m never sure whether this is related to something to do with the sensor insertion, or some other factor like me not being well enough hydrated for those days.

As long as it’s only 1ish out (or less) that seems like usable data to me. Consistently out by 2 or more begins to have a detrimental effect on my decision making, even if it’s a fairly consistent ‘error’ in the same direction each time. Somehow my brain can’t get past the number it sees!


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## Johnsgirl (Aug 4, 2021)

My partner has had issues with the sensor not working and the hot weather has been blamed.


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