Freestyle Libra 2 Sensor

[Valley1]

Yesterday I started using a free sample of the Freestyle Libra 2 Sensor and I‘m already frustrated with it and getting paranoid about my blood sugar levels. Recently I had my review with the diabetic nurse and my HbA1c reading had increased from 44 mmol/l a year ago to 50 mmol/l. She said this could be a bit of progression, which has worried me. I decided to try harder with my diet and was hoping this sensor could help me. However, the readings are all over the place and sometimes seem to be unrelated to what I eat. I’m getting high readings just from pottering around the house then they decrease when I’m sitting relaxing, doing nothing - this doesn’t seem right to me. Before I pull the sensor off in anger, if anyone can help, I would very grateful. ☺️ Thank you!

 

[MrDaibetes]

Hi there, have you checked these with your fingerpricks to make sure it is accurate?

There's so much that can change our blood glucose levels from stress to relaxing to eating to exercise.

Maybe when you're sitting relaxing, this is making your sugars more in range as you may not be stressed when pottering about do you get stressed?

 

[Satan’s little helper]

Hello, I can appreciate first time use can be a revelation. You will notice trends, given more time.
I have to admit, I can see trends like that when in tricky situations. I’m normally calm and measured. People will tell me, “you took that well.” Then I pull up the graph. Best wishes.

 

[Valley1]

Thanks for the reply. No I haven’t checked with fingerpricks, maybe will do. I don’t get stressed when I’m pottering, I’m just doing stuff like getting ready for the day! I didn’t think this sensor would also measure your stress levels umm!

 

[rebrascora]

What sort of variation are you seeing?
Our levels go up and down throughout the day and night in response to something like 42 factors, some of which we have control over but many we don't, so it isn't by any means predictable what BG levels will do. For instance vigorous exercise will usually push your levels up at the time but will reduce them later. Prolonged aerobic exercise will slowly lower them and continue to lower them for up to 48 hours afterwards. Food will usually raise them, so you might have the effects of exercise lowering them whilst you have food increasing them so it can appear that things are not doing what you expect when you expect it. It is extremely complex. Added to that there are a number of limitations and quirks which CGM and Libre in particular display. Things like compression lows if you apply pressure to the arm with the sensor, like lying on it during your sleep. The system also uses an algorithm to predict what your BG will be because it is actually taking a reading from interstitial fluid which tends to lag behind Blood Glucoe by about 15 mins. The algorithm works by extrapolating the current readings to predict the current reading, which is fine when levels are stable or going uniformly up or down, but if they are changing at a different rate ie, have been rising fast but are leveling off or conversely they were dropping fast but now levelling off, the Libre extrapolation will continue to show them rising or falling fast until it gets it's next lot of data, which means it will often suggest you are lower than you are or higher at the upper and lower end, but when it draws the graph, it will smooth out these high and low readings, so you may see a reading marker hanging above or below the graph line. This issue is worst when levels have been rising or falling fast, but then change direction like at the peak of a spike or the trough of a dip.
There is a list of the limitations of CGM in the Pumps and Technology section I will link below, but please don't discard it yet until you understand better how it works. It is a really amazing bit of kit once you learn to live with it's foibles.

CGM limitations and precautions

Moderator Note: This helpful reply was copied from another thread as it details some of the commonly experienced limitations of continuous glucose sensors. My blood sugar has been in perfect range for days now, but although I haven't changed anything, I'm starting to get very short periods of...

forum.diabetes.org.uk

 

[Inka]

If you only inserted the sensor yesterday, it might still be settling a bit. I found the first 24-48 hours could be a bit erratic with some sensors, but it then settled. Usually they take a day or so to settle.

Give it the full 14 days before you make your judgement about its usefulness.

 

[Proud to be erratic]

Thanks for the reply. No I haven’t checked with fingerpricks, maybe will do. I don’t get stressed when I’m pottering, I’m just doing stuff like getting ready for the day! I didn’t think this sensor would also measure your stress levels umm!

I love the umm! It says so much so succinctly and would not need translating to many other languages.

Stress (one of those 42 factors) generally results in increased BG (there may be folk who don't get stress response). So Libre is simply telling you what you couldn't previously see! Once it has raised your BG that extra glucose from your liver's glucose store is there and you now know (thanks to Libre), you can try to ease it back down with some exercise or at least reduce any planned carb intake with your next snack or meal.

 

[Valley1]

What sort of variation are you seeing?
Our levels go up and down throughout the day and night in response to something like 42 factors, some of which we have control over but many we don't, so it isn't by any means predictable what BG levels will do. For instance vigorous exercise will usually push your levels up at the time but will reduce them later. Prolonged aerobic exercise will slowly lower them and continue to lower them for up to 48 hours afterwards. Food will usually raise them, so you might have the effects of exercise lowering them whilst you have food increasing them so it can appear that things are not doing what you expect when you expect it. It is extremely complex. Added to that there are a number of limitations and quirks which CGM and Libre in particular display. Things like compression lows if you apply pressure to the arm with the sensor, like lying on it during your sleep. The system also uses an algorithm to predict what your BG will be because it is actually taking a reading from interstitial fluid which tends to lag behind Blood Glucoe by about 15 mins. The algorithm works by extrapolating the current readings to predict the current reading, which is fine when levels are stable or going uniformly up or down, but if they are changing at a different rate ie, have been rising fast but are leveling off or conversely they were dropping fast but now levelling off, the Libre extrapolation will continue to show them rising or falling fast until it gets it's next lot of data, which means it will often suggest you are lower than you are or higher at the upper and lower end, but when it draws the graph, it will smooth out these high and low readings, so you may see a reading marker hanging above or below the graph line. This issue is worst when levels have been rising or falling fast, but then change direction like at the peak of a spike or the trough of a dip.
There is a list of the limitations of CGM in the Pumps and Technology section I will link below, but please don't discard it yet until you understand better how it works. It is a really amazing bit of kit once you learn to live with it's foibles.

CGM limitations and precautions

Moderator Note: This helpful reply was copied from another thread as it details some of the commonly experienced limitations of continuous glucose sensors. My blood sugar has been in perfect range for days now, but although I haven't changed anything, I'm starting to get very short periods of...

forum.diabetes.org.uk

Ahh thanks for this detailed reply. I get it and will bear with it and try not to worry too much about the highs and lows! It will be interesting to see the end result!

 

[Valley1]

If you only inserted the sensor yesterday, it might still be settling a bit. I found the first 24-48 hours could be a bit erratic with some sensors, but it then settled. Usually they take a day or so to settle.

Give it the full 14 days before you make your judgement about its usefulness.

Ok, will do! Thank you ☺️

 

[everydayupsanddowns]

Hope the readings settle down and start providing you with helpful information that you can turn into positive action. 🙂

 

[Robin]

Do you take in enough fluids? If you’re dehydrated, the sensor can read lower if it’s compressed, so check if you are squashing it when you sit down. I’ve just had a tummy bug, and got very dehydrated, and looking at my overnight graph, I can see exactly when I turned over in bed and lay on the sensor, my graph is a zig zag all night.

 

[Teadance]

I struggled when I first started using my free sample, but now find it incredibly useful. I learned to ignore the first couple of days readings as it was suggested that the tiny ‘wound’ caused by inserting the probe might interfere with a true interstitial fluid reading. Originally I thought this was wasting a couple of days of using the Libre 2, until someone on here suggested applying the sensor and NOT activating it for a couple of days. That way it gives the ‘wound’ time to heal and you get the full 14 days of more accurate readings. Let’s face it, they’re not cheap! But I’ve found using them occasionally incredibly helpful and informative. Good luck.