Libre reading discrepancies

[barrym]

I'm a newish user of the Libre. I had a one sensor trial back in March and took the plunge to buy my own this month.

I'm 5 days into first sensor and generally I'm very pleased with the convenience. However, yesterday and today I've had lows that haven't registered on the Libre.

For example this morning I got back from a walk with the dog and felt low, and had been for a good few minutes, maybe 10. I tested with Libre and it showed 5.8! With meter 2.8. OK, I though that it was down to the 10-15 minute delay but I continued to check the libre every few minutes and it didn't drop at all.

I checked the Libre when I started off comparing meter, app and reader and all was good, within 1 mmol.

Is this likely to be a regular occurrence at the bottom of the range?

Anyone else seeing this? Kind of spoils the benefits of the convenience to my mind.

 

[GrantGam]

I'm a newish user of the Libre. I had a one sensor trial back in March and took the plunge to buy my own this month.

I'm 5 days into first sensor and generally I'm very pleased with the convenience. However, yesterday and today I've had lows that haven't registered on the Libre.

For example this morning I got back from a walk with the dog and felt low, and had been for a good few minutes, maybe 10. I tested with Libre and it showed 5.8! With meter 2.8. OK, I though that it was down to the 10-15 minute delay but I continued to check the libre every few minutes and it didn't drop at all.

I checked the Libre when I started off comparing meter, app and reader and all was good, within 1 mmol.

Is this likely to be a regular occurrence at the bottom of the range?

Anyone else seeing this? Kind of spoils the benefits of the convenience to my mind.

Hi @barrym,

My experience with the Libre was that it very much over-exaggerated highs and over exaggerated lows. So in your situation, when the Libre finally caught up with my actual BG - it would have been lower than 2.8mmol/l on the reader.

I'd give Abbott a ring and dicuss replacement options with them. Being 5 days in, the sensor should be well settled and giving you readings very close to your finger prick tests, once factoring in the delay. The fact that it didn't register a hypo is worrying and warrants a replacement sensor IMO. Your meter should be mirroring what happens to your BG (even if it's slightly delayed) - it appears that yours is not.

Even if you're finger prick at 2.8mmol/l was slightly out and it was actually a 4mmol/l (I'm not saying it was, hypothetically speaking) then that's still a discrepancy of 1.8mmol/L at the lower end of the BG range, which in my eyes is no use.

Abbott customer services are very helpful so your request for a replacement will likely be granted

Let us know how you get on!

 

[DCUKMod]

@barrym - I'd suggest prior to ringing Abbott you do a little prep, to bring your figures into a succinct explanation. They're only going to be interested in the numbers, and as many iterations as you can evidence to them. I usually also check (for myself) the percentage variation on both Libre and meter readings to ensure they're reasonable to challenge.

I have never, ever, asked for a sensor to be changed, but have called explaining my Libre isn't reacting as I might hope, then go on to explain. When I have called using this approach, I have never been disappointed.

The only time there wasn't an immediate replacement offered was when the sensor was very early in it's life and I was asked to give it a further 24 hours, to see if it settled better.

Their preference is definitely that comparative readings are from their own meters; for fairly obvious reasons.

Good luck with it all.

 

[barrym]

Just got off the phone with Abbott. Extremely helpful. I too din't ask for a replacement, just to understand the situation. I was able to give comparative readings with my meter (not theirs) a Accu Check Mobile which he seemed happy with. Their fault finding system steered us to a displaced sensor which I'm not convinced by. I've been very careful not to disturb it. Anyway they want to swap it out and see what they can from the old one. I guess with new tech like this they do need as much data as they can get. To be honest, there's no real advantage to me in a swap, OK I save a few quid, but that's not really the point. I'd much prefer a hard reason for the discrepancy so I can trust the thing. I'm already questioning whether I really get any advantage over my meter. It is very nice to see what happened between readings but only if accurate.

 

[Wjohn]

I feel for Barrym and Abbott with this .Ive been a type 1 ,55yrs and Libre 9 months ,and I find that the convenience of Libre combined with its more than reasonable accuracy is great . Abbott do say that finger pricking should be done if the Libre indicates a extreme upward or downward trend .So when you get to the stage after 20+ years of finger pricking and it now takes 2or3 pricks to get blood from a thick skin ,accept that the Libre system does in some cases require to be confirmed ,and that it is a terrific advance and benefit to diabetics .
PS. I would be delighted if I was able to achieve the BG readings you provide ,
wjowen

 

[barrym]

I guess it doesn't matter what the numbers are, if you don't feel in control it's frustrating. I got told a 'normal' person would be 4 to 7 so that's my aim. If I slip outside these, which I frequently do, I get annoyed with myself and the disease. My DSN hates the fact I try so hard, as she can tell from my hba1c that I must have had lots of lows, and my last meter dump showed 40% low. But my defence is that the tighter the control, the smaller the margin for error, over or under.

 

[Wjohn]

Yes be aware of the 4 to 7 ,but these are for ,healthy non diabetics ,we are not ,and so have to find methods to compensate .All the algorithms,terrific new developments,pumps etc will never get us into the perfect region of 4 to 7 ,so don't beat yourself ,try and find the best for yourself and go with it but be prepared to adjust your levels according to circumstances,the occasional 12 or 13 s will happen,but you will at sometime need these levels depending on activity levels .I frequently go to these levels whilst playing a round of golf ,
Wjohn

 

[barrym]

Yes be aware of the 4 to 7 ,but these are for ,healthy non diabetics ,we are not ,and so have to find methods to compensate .All the algorithms,terrific new developments,pumps etc will never get us into the perfect region of 4 to 7 ,so don't beat yourself ,try and find the best for yourself and go with it but be prepared to adjust your levels according to circumstances,the occasional 12 or 13 s will happen,but you will at sometime need these levels depending on activity levels .I frequently go to these levels whilst playing a round of golf ,
Wjohn

Agree with all that. I do put up with higher spikes, but lows are a nuisance on so many levels.

Interestingly my DSN sent me a link a few months ago saying that new research suggested that short term spikes were not harmful, only long term elevated levels. It was a research paper and not an easy read and I didn't keep the link. It does make sense though, or wishful thinking? I like to think the former.

 

[Bon83]

It may be me being slow to catch on but I had a bit of a eureka moment with my libre regarding the time delay. I treat every reading like it was 15 mins ago - this may seem obvious but I wasn't getting it for ages! I have therefore found it more accurate just that the time delay is really important for me. I have also questioned it's usefulness for me. If you have really stable blood sugar levels over several half hour periods then it can be pretty bang on. I would love to acheive that - but with exercise and housework I can't - last night for example I dropped really quickly and the libre was lagging behind my meter - the readings were accurate just behind. 10 mins is a lot when your on a rapid drop. I think what I'm trying to say is that I probably needed more specific education on how to use it - which Abbott may not want to over advertise.

Sent from my SM-G900F using Diabetes.co.uk Forum mobile app

 

[barrym]

I was just talking to my DSN about this, and I put forward a theory that I want her to check.

If levels fall quickly, and you react to if quickly as I did in this instance, it may only get caught by one or possibly two readings, possibly even none! The algorithm for converting to mmol may well have a smoothing built in to stop it looking like saw teeth. Makes sense. I hope she does ask, but I doubt an answer any time soon.