FREESTYLE LIBRE 2 TIME DELAY

[mum2westiesGill]

Apparently the freestyle libre 2 doesn't have the time delay that the freestyle libre 1 had - please can someone confirm this?

 

[helli]

The delay is not as bad with Libre 2 but if my levels are falling or rising quickly, the delay can be noticeable.
For example, when I am correcting a hypo, with fast acting carbs and hoping my levels rise quickly, Libre 2 is slow in noticing the rise.
But for standard meal dosing when I haven't just been for a run (which causes my levels to drop fast), I am happy to trust Libre 2.

 

[nonethewiser]

Just find 2 more accurate overall than 1, so far not had one fail or issues with one.

 

[leonS]

The delay is caused (nainly) because the libre does not measuew the blood but uses the general body fluid, which follow the blood glucose level. This is a drawback of the technology and results in a delay of 15 minutes or so.

Libre 2 technology is the same as Libre 1, so I do not see that there can be any great improvement in response time.

 

[trophywench]

Have to say, so far the 2 seems better aligned to my actual BG than the 1 ever did Only trouble with it is I've had a couple simply fail to communicate with the reader and of course when you only get 2 at a time on prescription you haven't yet ordered the next script from the Drs, so then you get another gap and takes at least a week for Abbott to get a replacement to you - but at least they do replace them providing the error codes are properly relayed to them. Current one is working OK but my BG has been very up and down the last week, so then the Libre is less reliable very high or low anyway.

 

[mikeyB]

The Libre 2 is much more accurate going low (I’ve checked it), but just as slow coming out of a hypo. Haven’t been high enough to check the upper limit.

 

[Lucyr]

The delay is caused (nainly) because the libre does not measuew the blood but uses the general body fluid, which follow the blood glucose level. This is a drawback of the technology and results in a delay of 15 minutes or so.

Libre 2 technology is the same as Libre 1, so I do not see that there can be any great improvement in response time.

I imagine they’ve updated the algorithm that predicts forwards what will happen to your bg, to better account for the time lag.

 

[mikeyB]

I doubt that very much, @Lucyr, that would be dangerous. Apart from anything else, you can’t make the delay any shorter, because that’s the way the body works if you are sampling interstitial fluid.

 

[Robin]

I imagine they’ve updated the algorithm that predicts forwards what will happen to your bg, to better account for the time lag

I doubt that very much, @Lucyr, that would be dangerous. Apart from anything else, you can’t make the delay any shorter, because that’s the way the body works if you are sampling interstitial fluid.

There is an algorithm to catch it up a bit, and they have recently improved it.

Error - Cookies Turned Off

onlinelibrary.wiley.com

Sorry, it doesn’t look as if that link is working, though it works for me. If not, try Googling 'Libre new algorithm' and it's the top hit.

 

[Lucyr]

I doubt that very much, @Lucyr, that would be dangerous. Apart from anything else, you can’t make the delay any shorter, because that’s the way the body works if you are sampling interstitial fluid.

I don’t think you understand how the libre works. When it gives you a reading that isn’t your actual blood glucose. It’s an estimate based on your interstitial fluid and the direction that estimate has been going in to compensate for the delay to blood. That’s why the level sometimes changes quickly.

 

[mikeyB]

You are talking talking to a doctor. I know exactly how a Libre works, and understand the science, so do not talk to me like I am stupid.

In words of a few syllables as possible, the sample is taken from interstitial fluid. If the BG changes, it takes a short time for the interstitial blood to catch up. The Libre presents the reading from interstitial fluid. An algorithm can to some extent compensate for that reading at that time, but what it cannot predict is what the reading in ten minutes time will be. That wouldn’t be an estimate, it would be a guess, hoping that you hadn’t swallowed half a pint of Orange juice.

The algorithm compensates for the fairly standard difference between the BG and interstitial fluid reading, because that difference is always there. It does not predict anything, and it cannot compensate for the delay in monitoring change, because as I originally said, that’s how the body works. It will always be there.

 

[Lucyr]

You are talking talking to a doctor. I know exactly how a Libre works, and understand the science, so do not talk to me like I am stupid.

In words of a few syllables as possible, the sample is taken from interstitial fluid. If the BG changes, it takes a short time for the interstitial blood to catch up. The Libre presents the reading from interstitial fluid. An algorithm can to some extent compensate for that reading at that time, but what it cannot predict is what the reading in ten minutes time will be. That wouldn’t be an estimate, it would be a guess, hoping that you hadn’t swallowed half a pint of Orange juice.

The algorithm compensates for the fairly standard difference between the BG and interstitial fluid reading, because that difference is always there. It does not predict anything, and it cannot compensate for the delay in monitoring change, because as I originally said, that’s how the body works. It will always be there.

Thanks for implying all of us non doctors are not intelligent enough to understand here but you don’t have to be a doctor to read that the accuracy is improved with libre2 because of the updated algorithm. There will always be a difference. It’s less now because they’ve changed the formula that they use to estimate your blood glucose from your interstitial fluid.

 

[Lucyr]

From the link above, MARD of 11.3 with libre 2 vs 13.7 with libre 1, backs up the improved accuracy from the updated algorithm.

 

[Robin]

From the link above, MARD of 11.3 with libre 2 vs 13.7 with libre 1, backs up the improved accuracy from the updated algorithm.

Thank you, Lucy, that’s the study I was trying to link to. @mikeyB , don’t you ever get a high reading if you swipe when your BG is rising sharply, which then never appears on the graph when you look later? Anything that catches up an interstitial reading with a blood glucose reading is by definition making a prediction. I assume that sometimes one of the predicted measures didn’t pan out when the Libre did its next routine measurement, so it ignores it for the purposes of producing the graph. I also assume that when you get a ‘try again in 10 minutes' that’s when the algorithm has decided that your readings are just too variable for it to make an accurate prediction.
Nobody is saying it’s trying to predict beyond the limitations of Blood Glucose, which have a delay in themselves. It’s not plucking figures out of the air, but if you have just necked a pint of orange juice, then it will either make a wrong prediction, or it will defeat the algorithm and it’ll tell you to come back when it’s sorted itself out.