Higher readings on Freestyle Libre

RPa

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Type 1
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Hi

I started using the Freestyle Libre 2 days ago. I have been excited at the thought of using this, as I have been type 1 for 31 years now and I was looking forward to reducing the number of times i test my blood. However I feeling quite disappointed with the freestyle, it always shows my readings to be about 5mmol/l higher than testing my blood.
Is there something wrong with sensor? Or does this happen when you first start using the freestyle?

Thanks
 

Antje77

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A bit difference can be expected. If your numbers are very high, the difference will be bigger.
 
D

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I find the Libre Reader and Libre app are often a long way out. Especially at higher or lower values.
However, I find my Libre readings are closer to finger pricks when I use the Glimp app. This may be because Glimp,uses a different algorithm to convert interstitial,fluid readings to BG readings including calibration from finger pricks.
 
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hh1

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Hi

I started using the Freestyle Libre 2 days ago. I have been excited at the thought of using this, as I have been type 1 for 31 years now and I was looking forward to reducing the number of times i test my blood. However I feeling quite disappointed with the freestyle, it always shows my readings to be about 5mmol/l higher than testing my blood.
Is there something wrong with sensor? Or does this happen when you first start using the freestyle?

Thanks
Hi @RPa, I've been using Libre for over 18 months now. I had a couple of dodgy sensors at first, and whilst I agree with @Antje77 that the higher (or lower) your bg, the larger you may find the discrepancy with Libre, I wouldn't tolerate the value difference you're seeing. I'd phone Abbott and tell them and ask for a replacement sensor. I had no trouble getting mine replaced. Be sure to have some examples of discrepancies in readings between Libre and your meter when you call, I'd suggest a minimum of three. Good luck!
 
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Scott-C

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Is there something wrong with sensor?

Hi, RPa, I've been using libre for about two and a half years now, so about 60 or so sensors in.

Each has a different "personality": some sensors I trust, some are totally dingbat. Use them for a while and it's easier to figure out which are good and which are sketchy.

Fortunately, there's only been about 4 or 5 out of the 60 which have been throwing totally random results like yours (and even those have been ok for a fair bit of the time).

I think you might have just been unlucky in getting a dubious one as your first - they're really not all like that.

Abbott are normally pretty good at replacing the really duff ones and being 5 out certainly does sound like a duff one, so give their helpline a phone, they'll ask you to do a bg test while you're on the phone, compare it to a scan 10 mins later, then fire you a new one for free if it's too far out.

It takes a bit of work to get used to them, but it's time well spent. In the first week I used it, I tested lots, every hour or so, just to get an idea of difference between bg and the ifg (interstitial fluid glucose) which libre is measuring.

Doing it that way, you get a better idea of why there is a "lag" between the two, so you can end up saying, ok, libre says 5 which means bg is probably 6.5, and learn ways to work round that.

Took me about 5 months to be ok bolusing from it, but I got there.

Many people think libre is "plug and play". It's not - it takes time to understand how to read it, but it pays in spades when you learn how to do it.

A part of that is learning how to identify dodgy sensors, they're not all like what you've had, so I'd encourage you to persevere with it, even though your first one has been disappointing.

A lot of us are pimping our libres with small transmitters on top, about £100 for blucon, £160 for miaomiao, they ping readings from libre every 5 mins to an app, so you get full on cgm, hypo alerts, that sort of stuff. You can also feed bg readings into the app, which really tightens up sketchy sensors, although I doubt it would deal that well with one which is 5 out.

Good luck with it, they're well worthwhile once you get used to their quirks!
 
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Antje77

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whilst I agree with @Antje77 that the higher (or lower) your bg, the larger you may find the discrepancy with Libre, I wouldn't tolerate the value difference you're seeing.
Depends. If it's a difference between 19 and 24 mmol/l I think it's acceptable if it's between 2 and 7 no way.
 

Scott-C

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Depends. If it's a difference between 19 and 24 mmol/l I think it's acceptable if it's between 2 and 7 no way.

I agree with that. Libre's good most of the time when in range, but it can throw some serious flyers when out of range and that's the point when you've got to say, nah, not trusting this, what does the strip say?

Although, to be fair, it can occasionally throw some nonsense when in range too.

I've got a copy of William Lee Dubois' book Beyond Fingersticks on kindle. It's about cgm and was written about 10 yrs ago, which means it's like prehistory in cgm terms, but he makes the still valid point that, although cgm is generally brilliant, you still have to know its limitations and identify when it's telling you rubbish and time to get the strips out.
 

RPa

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Type 1
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Hi, RPa, I've been using libre for about two and a half years now, so about 60 or so sensors in.

Each has a different "personality": some sensors I trust, some are totally dingbat. Use them for a while and it's easier to figure out which are good and which are sketchy.

Fortunately, there's only been about 4 or 5 out of the 60 which have been throwing totally random results like yours (and even those have been ok for a fair bit of the time).

I think you might have just been unlucky in getting a dubious one as your first - they're really not all like that.

Abbott are normally pretty good at replacing the really duff ones and being 5 out certainly does sound like a duff one, so give their helpline a phone, they'll ask you to do a bg test while you're on the phone, compare it to a scan 10 mins later, then fire you a new one for free if it's too far out.

It takes a bit of work to get used to them, but it's time well spent. In the first week I used it, I tested lots, every hour or so, just to get an idea of difference between bg and the ifg (interstitial fluid glucose) which libre is measuring.

Doing it that way, you get a better idea of why there is a "lag" between the two, so you can end up saying, ok, libre says 5 which means bg is probably 6.5, and learn ways to work round that.

Took me about 5 months to be ok bolusing from it, but I got there.

Many people think libre is "plug and play". It's not - it takes time to understand how to read it, but it pays in spades when you learn how to do it.

A part of that is learning how to identify dodgy sensors, they're not all like what you've had, so I'd encourage you to persevere with it, even though your first one has been disappointing.

A lot of us are pimping our libres with small transmitters on top, about £100 for blucon, £160 for miaomiao, they ping readings from libre every 5 mins to an app, so you get full on cgm, hypo alerts, that sort of stuff. You can also feed bg readings into the app, which really tightens up sketchy sensors, although I doubt it would deal that well with one which is 5 out.

Good luck with it, they're well worthwhile once you get used to their quirks!

Thank you Scott-C for your reply. It’s made me feel a bit positive towards the Libre. I will keep at it. I think I will give Abbot a call re: the sensor I’m wearing at the moment, it is still showing quite a big difference in readings between my meter and Libre.
 
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RPa

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Type of diabetes
Type 1
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Hi @RPa, I've been using Libre for over 18 months now. I had a couple of dodgy sensors at first, and whilst I agree with @Antje77 that the higher (or lower) your bg, the larger you may find the discrepancy with Libre, I wouldn't tolerate the value difference you're seeing. I'd phone Abbott and tell them and ask for a replacement sensor. I had no trouble getting mine replaced. Be sure to have some examples of discrepancies in readings between Libre and your meter when you call, I'd suggest a minimum of three. Good luck!

Thanks hh1. I will probably give abbot a call about this.
 
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ChrisJ_SLH

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I find the Libre Reader and Libre app are often a long way out. Especially at higher or lower values.
However, I find my Libre readings are closer to finger pricks when I use the Glimp app. This may be because Glimp,uses a different algorithm to convert interstitial,fluid readings to BG readings including calibration from finger pricks.

I'm glad I found this thread as it sort of confirms what I have found with the Libre since I started my first sensor on Saturday.

'In range' the Libre readings via the Libre app on Android correlate fairly closely with my Accu-Chek Mobile meter. Readings above 9mmol/l deviate to an increasing degree the higher they get. The worst I've seen so far are around a 2.5mmol/l discrepancy. As often reported, I also observed the initial poor performance (first 12~24hrs after activating) that is widely reported.

I've also been double reading with Glimp and importing BG meter readings into Glimp via the Accu-Check Mobile wireless adapter which have resulted in very close reading between Glimp and the Accu-Check when you factor in the interstitial delay. Glimp, while not as polished as the official app, definitely gives more useful data.

Overall I have been impressed with my so far limited three day experience. I prick-tested loads Saturday & Sunday to see how things were correlating and I'm slowly gaining confidence in the system. I've also ordered a MiaoMiao as this seems like something of a dream ticket for me at the minute. No doubt the Libre 2 will probably negate the need for the MiaoMiao but who knows when that will be widely available in the UK.
 
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