Libre Accuracy - how confident are you to trust it completely?

cumbria-pumper

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So I've compared my blood glucose with the Libre readings (usually about 10-20 minutes after) over the past two days. (I've been using Libre now for 9 days.) In my case it is always out - on average by 1.1mmol (but includes some higher and others lower - normally higher). I wonder if this is consistent with other people's experience? Although I like the convenience (especially when out and about to make a quick check) and the trends (it helps me to see when I'm going high or low) I don't think I can trust it enough to replace blood testing when bolusing/going to bed.

upload_2017-9-27_9-58-30.png
 
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tim2000s

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@cumbria-pumper Calculate the percentage difference on all those readings then if a majority are more than 15% away, contact Abbott for a replacement.
 
D

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The Libre is marketed as a replacement for finger pricking.
In my mind this is not the case. The value for a Libre is not the individual point in time readings. It is the history and trend information.
There are multiple reasons why the Libre does not provided the same reading as a finger prick which have been discussed previously. But looking at your numbers it is difficult to make any conclusions without knowing what else was happening at the time. For example, given there is a 15 minute delay with the Libre, this could explain the Libre being significantly different to finger pricking when exercising or eating high GI food: when your BG is changing quickly.
I have used Dexcom and Libre and found the Dexcom more accurate ... but more expensive. Therefore, I have chosen to self fund the Dexcom for occasional use.
If I get offered the Libre on prescription, I will take it but as a chance to review trends such as when eating certain foods or doing exercise and adjust my pump settings accordingly. I will continue to finger prick for driving and most bolus injections.
 

cumbria-pumper

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The Libre is marketed as a replacement for finger pricking.
In my mind this is not the case. The value for a Libre is not the individual point in time readings. It is the history and trend information.
There are multiple reasons why the Libre does not provided the same reading as a finger prick which have been discussed previously. But looking at your numbers it is difficult to make any conclusions without knowing what else was happening at the time. For example, given there is a 15 minute delay with the Libre, this could explain the Libre being significantly different to finger pricking when exercising or eating high GI food: when your BG is changing quickly.
I have used Dexcom and Libre and found the Dexcom more accurate ... but more expensive. Therefore, I have chosen to self fund the Dexcom for occasional use.
If I get offered the Libre on prescription, I will take it but as a chance to review trends such as when eating certain foods or doing exercise and adjust my pump settings accordingly. I will continue to finger prick for driving and most bolus injections.

I looked for Libre scans about 15 mins after as I've read it typically takes 10-20 mins for blood glucose to show up in interstitial fluid. Agree about when rapid change is happening.

Is there an app or other way to obtain the interpolated readings from the Libre at any time? The Libre view and Diasend sites show graphs of the curve but you can't accurately find a value at any given time.
 

bruce_no1

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I use the Glimp app on my android phone, it allows for a finger stick reading to be entered as a calibration. Works well for me and I have managed to get Libre sensors that I would have call Abbot to complain about giving useable results.

The only down side for me is the lack of Diasend access with it, so I can't share my results with my DSN.
 
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barrym

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Is there an app or other way to obtain the interpolated readings from the Libre at any time? The Libre view and Diasend sites show graphs of the curve but you can't accurately find a value at any given time.

If you put the Diasend app on your phone in the reports section you can see dots, 15m intervals, and dragging the focus line to each dot shows the reading. Also the export from Diasend shows each individual reading.

HTH
 

barrym

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Phoned them and as one reading was 28% out they're sending a replacement.
I've been considering this, and if the meter is as much as 15% low and the libre 15% high it would get some of the results I see.
 

DunePlodder

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We are used to trusting our bg meters, but don't make the mistake of thinking your meter bg s are perfect. As Barry says, it can still be +/- 15% (older ones were +/-20%).

So even with the 9 & 11.6 values, if the "true" bg was 10.3 they would both be within tolerance.
Just playing devil's advocate here.. I know it feels a long way out.
 

Scott-C

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I have used Dexcom and Libre and found the Dexcom more accurate ... but more expensive. Therefore, I have chosen to self fund the Dexcom for occasional use.

There's a company called Ambrosia Systems which sells a bluetooth transmitter called Blucon Nightrider for just over £100, one off cost. Pop it on top of a libre sensor with a plaster and it bluetooths readings to xDrip+ so it can be calibrated with bg tests, and gives alerts. Have only been using it for a couple of days, but so far so good, pretty accurate against meter if cslibrated a couple of times a day. Cheap and cheerful way to turn fgm into cgm! Haven't used dexcom so can't compare.
 

Stefans

Active Member
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30
Type of diabetes
Type 1
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Insulin
I have been using libre for about 3+ months now, I almost never prick anymore, except the first day with a new sensor.
I have consistently gotten about 1 mmol/l lower values out of the libre compared to my finger pricks, it seems to be very consistent for me.

I have just today done a check of my libre vs finger prick, I used both Libre optima and accu check sticks.
This is the result.
upload_2017-10-1_23-1-28.png

I tried to take tests when my values would be stable, this was after lunch, a low carb lunch at about 12:00. I was surprised that it went up so much, but still within about 1 mmol/l, not so bad.

To note is the difference of the finger pricks, to have a change of 1 mmol/l just 1 minute later surprised me, the few times I have tested twice before I never had more than 0.3 - 0.4 diff.

All in all the test showed that (for me) the libre is almost 1 mmol/l to low. that is how I use it and it works very fine for me.
As I said I used to prick almost 10 times per day, now I do 1 or 2 tests for each new sensor.
BTW this was a sensor that was about 30 hours old.