Strange behaviour of Libre.. and why to test before correcting

Jon-Manchester

Well-Known Member
Relationship to Diabetes
Type 1
I had a very strange experience with the libre this morning, which reminded me why I should always do a finger blood sugar test before correcting.
Basically sat with a very steady line of 5.8-6.0 for the last 5 hours since waking up.
Then i get an alarm saying my blood sugar is 19.3!!?!
I panic and test my blood sugar and it says 5.9.... , scan the libre and it says 19... and 20 minutes later the Libre sensor is now saying 6.

Very strange but I am so glad i didnt go ahead and correct the +19 reading before i had done a finger prick check
 

LucyDUK

Administrator
Staff member
Relationship to Diabetes
Parent
Yes, it's so easy to become accustomed to taking the results at face value - and though usually you can these odd occasions do serve as a reminder to the advice to double check.

Might be worth a call to Abbott to see if they advise continued use of that particular sensor or whether they suggest replacing it - may be hard to keep confidently using the readings from that one.
 

everydayupsanddowns

Administrator
Staff member
Relationship to Diabetes
Type 1
Well done for instinctively double-checking @Jon-Manchester :)

The ones that catch me out are where I’ve ‘swagged’ a meal and I
could well have got things a bit wrong with my dose. Then I’m more likely to be too busy being annoyed with myself to have your moment of clarity!
 

Bexlee

Well-Known Member
I currently have a misbehaving sensor. I rang Abbott this morning and they said remove and replace if I can ( which I can) Mine is reading very low. Started playing up after a week climbing ok then Lo then normal again - if I don’t feel like it claims I always check.
 

MHK

New Member
Relationship to Diabetes
Type 2
I had a very strange experience with the libre this morning, which reminded me why I should always do a finger blood sugar test before correcting.
Basically sat with a very steady line of 5.8-6.0 for the last 5 hours since waking up.
Then i get an alarm saying my blood sugar is 19.3!!?!
I panic and test my blood sugar and it says 5.9.... , scan the libre and it says 19... and 20 minutes later the Libre sensor is now saying 6.

Very strange but I am so glad i didnt go ahead and correct the +19 reading before i had done a finger prick check
Some sensors are definately faulty. I reported to Abbot and they say they are normal we can expect to see a variation of 2 to 3 . For eg my sensor showed me 5.9 and finger prick is 8.9 and they say it is acceptable. I even lowered my medicine thinking that my sugars are getting normal. I don’t think a variation of anything more than 1 is acceptable considering the fact that I am paying A$100 for each. They should have strict quality control implemented.
 
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trophywench

Well-Known Member
Relationship to Diabetes
Type 1
Well what did the sensor read 10-ish minutes after the blood test? They aren't measuring the same thing anyway (Blood/interstitial fluid) so they'll never be precisely accurate and if you do 2 blood tests one after the other whether it's blood out of the same hole or from another finger, they won't be the same either. Nobody expects them to be precise.

BG meters should be within 10 ish percent either way but I have absolutely no idea what parameters the manufacturers of Flash glucose monitoring equipment have to work to! Who are the other manufacturers of them that we could ask?
 

Schrodinger

Well-Known Member
Relationship to Diabetes
Type 1
Well Libre I currently have attached is running anything between 4-8 mmols ahead of bloods. Phoned them and getting replacement sent. Have to do old school finger pricks for a bit LOL
 

Jon-Manchester

Well-Known Member
Relationship to Diabetes
Type 1
Yes, it's so easy to become accustomed to taking the results at face value - and though usually you can these odd occasions do serve as a reminder to the advice to double check.
It certainly is. So convenient so easy to forget

Well done for instinctively double-checking @Jon-Manchester
The ones that catch me out are where I’ve ‘swagged’ a meal and I
could well have got things a bit wrong with my dose. Then I’m more likely to be too busy being annoyed with myself to have your moment of clarity!


Mike, in all honesty, in a different situation I probably wouldn’t have been so quick to check. If this had been happening while I had a meal and not quite so high bs probably would have just gone ahead and just corrected it. So this was a really helpful reminder to not just believe the reading. I have been lucky in that Libre is almost always very close to my blood sugar reading


Well what did the sensor read 10-ish minutes after the blood test? They aren't measuring the same thing anyway (Blood/interstitial fluid) so they'll never be precisely accurate and if you do 2 blood tests one after the other whether it's blood out of the same hole or from another finger, they won't be the same either. Nobody expects them to be precise.


Well half an hour later after I had posted the post, sensor failed completely and I had to replace it (which was about an hour after the ‘high’). So the super high was obviously part of the failure
 
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Bexlee

Well-Known Member
Some sensors are definately faulty. I reported to Abbot and they say they are normal we can expect to see a variation of 2 to 3 . For eg my sensor showed me 5.9 and finger prick is 8.9 and they say it is acceptable. I even lowered my medicine thinking that my sugars are getting normal. I don’t think a variation of anything more than 1 is acceptable considering the fact that I am paying A$100 for each. They should have strict quality control implemented.

You say you’re paying A$100 each ? Are you in the UK? I’m assuming not. Maybe Abbott’s where you are are different to UK based? I had a sensor running 1.5-2.0 units low last weekend I rang on Monday and they said they’d replace (it arrived on Thursday) Over the last 6 months or so they defiantly seem more accurate and closer to finger prick
 

SB2015

Forum Host
Relationship to Diabetes
Type 1
I am amazed at the price you are paying in USA @MKH, and I think yours only last 10 days, or have they switched to 14 now?

As others have said the Libre is measuring a different thing from your BG meter so they are unlikely to match. The Libre is more useful for looking atoatterns and also for heading off highs and lows, by using the arrows. For me this has made a big difference. I have also found it great for reducing the spikes I was getting after meals, by timing my insulin or replacing/reducing portions.
 

everydayupsanddowns

Administrator
Staff member
Relationship to Diabetes
Type 1
I am amazed at the price you are paying in USA @MKH, and I think yours only last 10 days, or have they switched to 14 now?

I think it’s Australian dollars? So approx £55.
 
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