Libre 2 and tight control

[Baalmaden]

I have been type 1 for 30 years and after my son lost a leg and his sight from bad control decided to keep to a tight control regime. My health has been excellent and when I have my retinal scan the technician is amazed how good my retinas look. This has been very much aided by the Freestyle libre system which I have been using since it's inception, first paying and now getting my sensors and reader on the NHS. It has never been perfect, often giving readings below that tested by finger prick and for a while I had problems with skin reactions to the glue on the sensor. Luckily they solved that problem and I have managed to keep my long term test results to levels similar to a non diabetic. However since changing to the libre 2 sensor and reader I find that the readings are way below blood test readings - sometimes more than 2 mm per litre. This means that the sensor eventually stops working and I get a message to change it. It appears that Abbott has software that deliberately reads lower because they are afraid of users getting hypos. My hypo awareness is good and I find that I am sensitive to high blood sugars as well now. Fortunately Abbott has been replacing the sensors but I am afraid they will not do this forever. As a scientist I am used to instruments being calibrated accurately. If only you could use the strip reader included in the reader to calibrate the system.

 

[Juicyj]

Hello @Baalmaden I can't comment on the libre 2 as not a user, but I use the Dexcom G6 and swear by this system for accuracy and reliability, I started self funding also but was fortunate that the NHS now fund both my pump and the Dexcom as both systems are linked with Control IQ to regulate my BG levels, and have been using for around 4-5 years now, I rarely get fails, I think I had one last year, if you're unable to get funding via the NHS then it's worth self funding if this isn't an issue.

 

[Antje77]

If only you could use the strip reader included in the reader to calibrate the system.

I use the Libre2 with my phone and a third party app, DiaBox.
I started using it because it can be calibrated, but I found I'm also very happy with it continuously sending my BG to my phone without the need to scan.

You can still use the reader as well if you like.

 

[Tony337]

I agree with you @Baalmaden about the sensors reading lower than a finger prick test.
I too have good hypo awareness and can function normally in the early 3s below that and i can feel it.
Therefor i set the alarm at 3.9 and if it goes off i don't panic and just take a bit of carbohydrate to give me a slight lift.
This works for me and my last hba1c was 42 which is 6.0 in old money.
I am still aiming for lower and am in my 50th year of type 1.

Good luck
Tony

 

[Deleted member 527103]

What are your levels like?
I ask because the accuracy of all blood glucose monitors (CGMs and finger pricks) are expressed as a percentage of 15% accuracy.
For example, a "true" BG of 6.0 could be reported as 5.1 on one meter and 6.9 on another.
Or a "true" BG of 10.0. could be reported as 8.5 on one meter and 11.5 on another.
So a difference of 2 may not be that significant. It is just that we rarely compared two meters.

I never found Libre consistently lower. There again, like @Antje77 I have always used a third party app which allows me to calibrate the sensor to me. I found I needed to do the same for Libre 1.

 

[Antje77]

I never found Libre consistently lower. There again, like @Antje77 I have always used a third party app which allows me to calibrate the sensor to me. I found I needed to do the same for Libre 1.

I think it depends on the person, maybe there's variation in interstitial fluid between people or such. My Libres (both 1 and 2) have consistently read lower than blood by about 0.8 and 2.0 mmol/l for the past 6 years.
I can of course calibrate mentally but it still made me nervous to see numbers in the 3's so often when a fingerprick said 4's or 5's, and it led to me doing more fingerpricking than necessary.

Calibrating on DiaBox also makes things easier with my endo/diabetes nurse, they're happy to accept the calibrated values, which say I'm below 3.9 1 or 2% of the time rather than the LibreLink ones which usually says 7-12% low.
Calibrating saves me from having to 'prove' that I'm not low all the time.

It appears that Abbott has software that deliberately reads lower because they are afraid of users getting hypos.

I've thought that for a while, but it appears that for some people, like us, it reads consistently lower than blood, but for others, like @In Response , it's usually more or less spot on, and I've also heard of people for who it reads higher than blood. So they may simply be calibrated to be correct on average. I fully agree that adding the possibility to calibrate would be very helpful for the ones who want to.

 

[Newfiewatts]

I find my libre 2 reads consistently higher than my blood glucose monitor, sometimes by as much as 4mg higher. Also If out walking it often reads sensor not reading please try again in ten minutes, which is really annoying if you feel sugars are low.
I would be interested if anyone else has this problem?

 

[Deleted member 527103]

@Newfiewatts my understanding is that the "Please try again in 10 minutes" message occurs when our BG is changing quickly.
If you are seeing this when walking, it is likely that your levels are falling fast.

I agree it is inconvenient but it is just another reason why it is important to keep finger prick meter with you.

 

[RoughcutAU]

I find that when in range (4-8mmol) the libre is usually pretty close(within 1mmol) to fingerprick. However when low it tends to overstate the low and when high it tends to overstate the high.