FREESTYLE LIBRE ON SALE!!!!

[smidge]

It's always difficult when your BG is running at the low end of normal - it doesn't give the Libre or BG monitor any room for error. I think that's sometimes the problem with it for me - at mid control, the odd mmol either way is acceptable, but with tight control it isn't as it's a much bigger percentage error and could be disastrous.

My sensor has been a good 2mmol out at times this time - except having managed to get hold of a few test strips for the built- in meter, I've realised that on many occasions, my Libre sensor has run at 1mmol low and my Mobile has run at 1mmol high making the difference seem a bit dire - the built-in meter often shows the middle ground. Other times, all three have been within a few points of each other. I'll never really know which is the more accurate.

Smidge

 

[tim2000s]

I think what bothered me more wasn't the point reading, but the fact that the graph didn't show the drop and recovery that I felt. The graph simply showed a flat bg level, whereas what I felt was a definitive drop and recovery.

 

[misswhiplash]

Depends on your point of view. 3.3 v 4.3 is still a variance on the blood level of 30% or on the ISF level of 23%, both of which are a long way from the 15% MARD reference.

True, true...

 

[misswhiplash]

Though if you assume a bit of timing difference and look at the 4.4 vs 3.3, the 4.4 would only have to be 15% out to be actually 3.74 and the 3.3 only 13% out to be the same, which doesn't sound *so* bad

 

[tim2000s]

Though if you assume a bit of timing difference and look at the 4.4 vs 3.3, the 4.4 would only have to be 15% out to be actually 3.74 and the 3.3 only 13% out to be the same, which doesn't sound *so* bad

However, that's not the way that Abbott are quoting the variance

 

[smidge]

I think what bothered me more wasn't the point reading, but the fact that the graph didn't show the drop and recovery that I felt. The graph simply showed a flat bg level, whereas what I felt was a definitive drop and recovery.

I've taken Abbot to task on the lack of appropriate directional arrows several times - they just tell me that my BG moves too slowly to register. If it had no arrow at all to show complete confusion I'd understand it, but the horizontal arrow is very misleading at times. The manual actually explains how fast your BG has to be moving to show the slanted or vertical arrows - I've actually proved to them on at least two occasions that it was incorrect - they've taken all the data, but I've never had any feedback. In the meantime, I've learnt to take the directional arrows with a large pinch of salt.

I wonder if it was actually designed for the poorly-controlled diabetic whose BG zooms around!

Smidge

 

[TOMJC]

Depends on your point of view. 3.3 v 4.3 is still a variance on the blood level of 30% or on the ISF level of 23%, both of which are a long way from the 15% MARD reference.

Don't forget though that both machines have an accuracy threshold, so whilst there is a difference between the two meters you can't always blame it on the libre or indeed the BG meter. Eg if both are within the FDA approved range, one could be at the high end of the range the other at the low which actually means either meter is only ever half that difference away from your true BS level. Will be impossible without hospital tests to confirm which is right. Just means comparisons and reading should be taken with pinch of salt.

The beauty of the Libre (I don't actually have one yet so still waiting impatiently) is that a regular reading is taken and a line produced which means you still get to see the trend. Even if your reading is 10% out I would guess that most of your readings will be out by the same amount but the trend would be a reasonably fair depiction of your BS movements which I would argue is more useful in the long run than whether your reading is out by 1-2mmol. Better to focus on that than worry if individual readings are a few points apart.

Bit of a ramble but hopefully makes sense?

 

[robert72]

Don't forget though that both machines have an accuracy threshold, so whilst there is a difference between the two meters you can't always blame it on the libre or indeed the BG meter. Eg if both are within the FDA approved range, one could be at the high end of the range the other at the low which actually means either meter is only ever half that difference away from your true BS level. Will be impossible without hospital tests to confirm which is right. Just means comparisons and reading should be taken with pinch of salt.

The beauty of the Libre (I don't actually have one yet so still waiting impatiently) is that a regular reading is taken and a line produced which means you still get to see the trend. Even if your reading is 10% out I would guess that most of your readings will be out by the same amount but the trend would be a reasonably fair depiction of your BS movements which I would argue is more useful in the long run than whether your reading is out by 1-2mmol. Better to focus on that than worry if individual readings are a few points apart.

Bit of a ramble but hopefully makes sense?

Blood meters are not accurate enough to be exactly out by a fixed amount. The ±15% also allows for the variance between tests on the same meter.

 

[TOMJC]

Surely for the libre though we wouldn't expect there to be that much variance between each test? Otherwise the line would bounce all over the place. I get your point for normal BS meters as you test far less frequently but I would have though it might have been different for libre or am I mistaken?

 

[tim2000s]

The libre is constantly sampling, so I would expect that it would pick up a change over a period of time - that's what was missing.

 

[robert72]

Surely for the libre though we wouldn't expect there to be that much variance between each test? Otherwise the line would bounce all over the place. I get your point for normal BS meters as you test far less frequently but I would have though it might have been different for libre or am I mistaken?

The Libre is constantly sampling as @tim2000s says. I think it samples once a minute but it uses an average of samples and then predicts where it thinks you BG should be as it's measuring glucose in interstitial fluid rather than in blood. So whilst it doesn't bounce around, it is not always accurate either. I put a new Libre sensor on yesterday and it is quite erratic compared to fingerstick tests using it's built-in meter.

 

[TOMJC]

Surely for the libre though we wouldn't expect there to be that much variance between each test? Otherwise the line would bounce all over the place. I get your point for normal BS meters as you test far less frequently but I would have though it might have been different for libre or am I mistaken?

 

[TOMJC]

Sorry not sure why that posted twice. Thanks for response. Still fascinates me how big the accuracy threshold can be!

 

[robert72]

Surely for the libre though we wouldn't expect there to be that much variance between each test? Otherwise the line would bounce all over the place. I get your point for normal BS meters as you test far less frequently but I would have though it might have been different for libre or am I mistaken?

The Libre draws a pretty smooth line as it is averaging samples, but it still isn't that accurate. A graph from a blood meter might be more spiky.

Even the Libre scans don't agree with the averaging that draws the graph.
See the scan below at 3:00am yesterday showing 9.8 (the white blob) when the graph shows a level around 8.0. Most of the the othe scans (white blobs) are closer to the averaging graph. The black asterisks are blood tests done on the Libre's meter.

 

[TOMJC]

Got it. Think I just misunderstood how the libre works!

 

[TOMJC]

While I'm here, does anyone know what month we are up to in terms of offering to new people? I signed up in November but got no confirmation email so assume i didn't actually sign up (didn't know you were meant to get one) and so resigned up on 1st March. Guessing I have a long wait but just wondering how far down the queue I am

 

[asyarlk]

I signed up on the 15th Jan and received my meter yesterday. I am glad I've got it but I don't trust it yet, my readings are out by 1-2mmol each time which is a little bit annoying!

The graph is good though, although mine is a little worrying for bed time...

Just hope the accuracy improves a little

 

[GraemeJones]

Asyarlk - I know it can be annoying but remember that, each time you do a blood test or scan, the number given is not an absolute value. It is only accurate to plus or minus 20%. Your actual blood glucose value could be 5.0 for example, while a blood test could give 4.0 and the Libre scan 6.0 ( or vice versa). Ninety percent of the time my Libre readings have been more accurate than that, but the system shows trends, which single blood tests cannot.

Two points, why have you set such a narrow target range and why didn't you have a midnight snack, or were you asleep at the time?

Graeme

 

[LucySW]

Even the Libre scans don't agree with the averaging that draws the graph.
See the scan below at 3:00am yesterday showing 9.8 (the white blob) when the graph shows a level around 8.0. Most of the the othe scans (white blobs) are closer to the averaging graph. The black asterisks are blood tests done on the Libre's meter.

View attachment 13199

Yes. I quite often get way-out scan results and have come to disregard them. When doing my post-mortems (so to speak) on what went wrong or right the day before, I delete the scan column on the spreadsheet and use only the historic readings. Same for computing SD etc. They're better figures.

LSW

 

[asyarlk]

I was asleep at midnight so no snack! Yes I am aware my blue line is a bit thin, will increase my range!

I am hoping I can finger prick less and then use my libre at work. I am a teacher so finger pricking around 5 year olds can be hard work.

I understand the accuracy is an issue with all meters, therefore is it better to use one meter to avoid confusion? My hba1c was a lot lower than expected and I use the Glucomen lx plus which gives a rough average, whereas the libre is lower already.

Hope this makes sense!