I have completely lost confidence in Libre2. I have removed several and reported them to Abbot because of inaccurate readings but I find that they are regularly reading low. I put up with anything within 1-1.5 mmol lower or I would end up removing every one. However I have just had my annual blood test which tells me my HbA1C is 51 when my libre had consistently suggested I am at 44. I am getting really down about how I can effectively manage my HbA1C down if I am making decisions on a CGM which is regularly inaccurate. Am I overreacting?
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Lucyr
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Yeah I’d say so. The libre isn’t reading blood so it’s unrealistic to expect the estimated a1c to be the same as the actual one. The libre one is just basing its estimate on your average blood sugars. Two blood glucose meters testing the same drop of blood won’t give the same result, a margin of error is normal. You can usually still use the direction of change on libre to help manage your blood sugars.
Tdm
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No, thats a big difference. But if libre 2 doesn't suit, everyone is going to 2+ soon, or you could ask to try a dexcom. Thats what i did, i found the g6 works so much better for me. G6 isn't an automatic entitlement but dexcom 1 should be. They are a bit bulkier but its worth it for the reliability and accuracy
Jasmin2000
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I had the same issues a year ago when I realised that Libre2 just didn't work for my lifestyle (low carb, high protein, multiple intense exercise periods) and it gave me about 180 'lows' each quarter but only 5% out of range, due to the sensor's inability to track correctly the way BG does. In other words it was very often artificially low.
I now use Libre to get a bird's eye view of trends over the week/month, especially if I change routine, but I never make real-time decisions based on the CGM - that's where I still do finger sticks..
I now use Libre to get a bird's eye view of trends over the week/month, especially if I change routine, but I never make real-time decisions based on the CGM - that's where I still do finger sticks..
CGM can only estimate HbA1C because it reads something completely different.
For me, it was so far out (Libre estimated my HbA1C to be more than 20% lower than the actual blood test) that I decided it was just another thing to track if I wanted.
But HbA1C is not something I use to manage my diabetes.
I find the Libre very useful to manage my diabetes whilst understanding the known limitations of all CGMs.
For me, it was so far out (Libre estimated my HbA1C to be more than 20% lower than the actual blood test) that I decided it was just another thing to track if I wanted.
But HbA1C is not something I use to manage my diabetes.
I find the Libre very useful to manage my diabetes whilst understanding the known limitations of all CGMs.
I find it frustrating. Between the inaccuracies of the sticks and the variable inaccuracies of the libre I sometimes despair. I have blood test results on the way and will be interested to see how the Abbott HbA1C reading compares. It says 5.5 (old money) but I bet it's around 6.
Sometimes it's close enough and the stick machine and the libre are more or less in step, other times they are no way near agreement.
Sometimes it's close enough and the stick machine and the libre are more or less in step, other times they are no way near agreement.
Thanks this is really helpful. In summary I am expecting too much and I think I have to recalibrate my reliance.Are you familiar with this thread?
Bruce Stephens
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Yes, I think so. It may be worth trying Dexom One+ if Libre is enough out to cause you problems. Some people find Dexcom works better for them (and some find Libre works much better). However, a difference of 1 (or 1.5) compared to a test strip (which is itself not all particularly accurate) doesn't seem that bad to me. OK for day to day treatment, anyway, though it might well mean the HbA1c estimate would be unhelpful.
Proud to be erratic
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Excellent call, @Lisa.w. Lean on your Libre for trends, particularly changes from level BG to dropping.
I had 12 months of L2 being thoroughly unreliable, yet having any form of CGM was still a massive insight and advantage over the previous 12 months with only finger prick results. Most of the time I felt the product was poorly manufactured. But gradually I realised that many, many people were getting very acceptable results and the problem was me - my body and L2 were incompatible.
In mid '22 the NICE Guidance Note was revised and offered alternative CGMs. Today I think the main L2 competitor is Dexcom One+. The Dexcom G6 and G7 exist, but are in an increased cost bracket for the NHS and won't routinely be available to you at this stage, I suspect. Almost certainly you'd need to have at least tried the One+ first. The G7 is brilliant for me and much more akin to the L2+ or L3 in how it works; and is the same cost to THE NHS as the older G6.
Personally I think the CGM estimates, rather than the laboratory based tests, are invariably going to be a lottery and I wouldn't expect their predictions to be better than indicative. But nowadays, with CGM, Time in Range I think is a superior "guage"; it reflects reality for T1s and pretty well anybody on MDI. 70% TIR is excellent, so manage your expectations and don't strive for impossible targets.
I had 12 months of L2 being thoroughly unreliable, yet having any form of CGM was still a massive insight and advantage over the previous 12 months with only finger prick results. Most of the time I felt the product was poorly manufactured. But gradually I realised that many, many people were getting very acceptable results and the problem was me - my body and L2 were incompatible.
In mid '22 the NICE Guidance Note was revised and offered alternative CGMs. Today I think the main L2 competitor is Dexcom One+. The Dexcom G6 and G7 exist, but are in an increased cost bracket for the NHS and won't routinely be available to you at this stage, I suspect. Almost certainly you'd need to have at least tried the One+ first. The G7 is brilliant for me and much more akin to the L2+ or L3 in how it works; and is the same cost to THE NHS as the older G6.
Personally I think the CGM estimates, rather than the laboratory based tests, are invariably going to be a lottery and I wouldn't expect their predictions to be better than indicative. But nowadays, with CGM, Time in Range I think is a superior "guage"; it reflects reality for T1s and pretty well anybody on MDI. 70% TIR is excellent, so manage your expectations and don't strive for impossible targets.
Proud to be erratic
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I've had a real bad run with libres of late some dieing some being wildly off giving me constant lows when not. For me libre when working okay tends to be 1mmol lower roughly than a finger prick. So I always say to myself when looking at it think 1 above for me at least.
For me I don't use libre for dosing I only use finger pricking If I had used libre my levels would be all over the place bad highs/lows last two Hba1c 44/45. I understand the limitations/limits accuracy of both
I use libre for observing trends to give me an idea of which way my levels are moving as I find the trends it detects are pretty spot on.
When I speak to see my DSN/consultant I often have to explain most of the lows on libre aren't lows except for the odd ones they I say I finger prick etc that always gets a mixed reaction but is working well for me
For me I don't use libre for dosing I only use finger pricking If I had used libre my levels would be all over the place bad highs/lows last two Hba1c 44/45. I understand the limitations/limits accuracy of both
I use libre for observing trends to give me an idea of which way my levels are moving as I find the trends it detects are pretty spot on.
When I speak to see my DSN/consultant I often have to explain most of the lows on libre aren't lows except for the odd ones they I say I finger prick etc that always gets a mixed reaction but is working well for me
victorhamesse
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I've just sent a Libre2+ back to Abbott as it read 3.9 when my finger test read 6.5. Gave me false hypos all night and spoilt my 100% in range score ! Now I have one which is consistently 1 unit too high (probably acceptable). Just goes to show.
I used to use Dexcom1+ but junked them when a sensor refused to be recalibrated. They were also inaccurate as well as notoriously imprecise.
Overall I prefer the precision of the Libre2+ even though both types are not accurate, but are mostly accurate enough for my use. I also found Abbott Customer Service to be better.
I used to use Dexcom1+ but junked them when a sensor refused to be recalibrated. They were also inaccurate as well as notoriously imprecise.
Overall I prefer the precision of the Libre2+ even though both types are not accurate, but are mostly accurate enough for my use. I also found Abbott Customer Service to be better.
rebrascora
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You do know about "Compression lows" don't you, where if you apply constant pressure to the sensor for any length of time like lying on it in your sleep, it will give a false low (hypo) reading? It is one of the reasons why it is recommended to double check any lows or high readings with a finger prick before taking action, although after a while you learn to recognise compression lows because you are usually lying on that side when the alrm wakes you up and the graph tends to show a sharp dip, rather than a slow descent into the red that you usually get with a genuine nocturnal hypo unless you went to bed with active bolus insulin.
I find Libre usually reads about 1mmol lower than a finger prick with Caresens meter but I bought some Freestyle Optium test strips to use in my reader and they usually read very slightly lower than the Libre sensor. Generally my Caresens reflects how I feel, so if Libre says I am 3.5 but I don't feel hypo, Caresens usually says I am about 4.5. Yes, it messes up my TIR a bit and makes my hypo figures a little higher than they like, but I have to remember that without Libre I wouldn't have TIR at all and I really find that a useful function. I base all my injections and corrections off my Libre readings and find it gives me really good results but maybe part of that is that I follow a low carb way of eating, so I am rarely injecting large doses.
Personally, I absolutely love Libre and it has revolutionised my diabetes management but you have to understand it's limitations and quirks, most of which were compiled into a list by @helli and posted here
How do you know your finger prick test is accurate?
As well as the list shared twice in this thread, there is the assumption that finger pricks are accurate whereas if your sensor is consistently 1mmol/l different (regardless of BG?}, it is also possible the error is on the other meter or possibly both.
victorhamesse
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Correct. A difference of 1 unit is, to me, neither here not there. Within the tolerances marked on the test strip bottles. What is useful is a trend and consistency of difference between the two types of measurement.
victorhamesse
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Yes. The sensor is always on the uppermost arm when I sleep. I change sides of the bed every 15 days. Fortunately I don't need insulin (yet), so hypos are false alarms to me unless confirmed by my physical symptoms. I did have one once when I had walked too far and had to rest on a user-friendly public bench and guzzle some jelly babies.