Libre, how inaccurate is too inaccurate?

[Fndwheelie]

Ok, so this is probably a bit of a rant/moan about libre, but I want to know what you think is too far out to be accurate?

I guess I’ve been lucky, I’ve probably used 10 sensors since starting on it and I was happy enough with the scans Vs finger prick variations. Usually my libre is lower than finger pricks by 0.5-0.7 not really more than 1mmol/l which is fine I can see trends etc and I’m not under false pretences, nothing is 100% accurate. My sensor I attached Wednesday, and activated at 4pm yesterday (Thursday) didn’t look too bad yesterday evening, I never pricked to compare it. This morning when I woke up I scanned and it was too low to to give me a reading, but I was awake, refreshed and feeling fine. I have attached my comparisons, and libre graph for 24 hours, showing a lot of time in the red since starting the new sensor, but I don’t believe I was hypo at all.

I contacted abbot about 9am but they needed more comparisons before they do anything, I gotta phone back this evening. Would you be pressing for them to replace this sensor if you saw these variations in readings? What level of difference would/do you accept?

Edit: forgot to be specific about waiting to activate it.

 

[Fndwheelie]

Sorry I had a slight technical hitch with images, here they are.

 

[Fndwheelie]

@helensaramay thanks, I did wait 24 hours before activating the sensor, but I wasn’t clear in my original post. Being iOS I would love to be able to use spike to calibrate the sensor, but I don’t have a computer to install it every week. I’ve just brought the MiaoMiao 2 which I’m going to use with tomato, can I calibrate it with that?

 

[Fndwheelie]

Update: I phone abbot again this evening and gave them more readings, they have agreed to replace my sensor. I felt the difference was too high, and I didn’t like thinking I was hypo when I wasn’t, I felt it could have lead to me running my sugars higher than I need to.

 

[Robbity]

I've found that I've needed to allow 48 hours for my sensors to acclimatize before I get sensible readings - particularly overnight. This is what i saw after short term activation - logs are 24 hours midnight to midnight. ( I also found that lying on my sensor arm could sometimes cause slight lows.)


After this initial couple of days, these overnight low levels would return to normal. So now I just let sensors sit for 48 hours before activating, and if I use them continuously, I'll insert a new sensor 2 days ahead of existing one expiring. And no more weird lows!



MIne also always run a bit low but are generally consistent with the patterns from finger prick meal time, etc, tests (I'm T2 diet controlled so don't have to worry about insulin.)

Robbity

 

[shedges]

I'm the other way - my libre shows readings 2-3 points above the finger prick reading, which is demoralizing to say the least. I could be 4.0 on finger prick and it shows 6, I can be 9.2 and it'll show 12 ... and this is all the time, not just first 24/48 hrs.