Kinda intresting update to my ongoing sensor issues (salicylic acid)

[helli]

It’s a clumsy metaphor but I hope it helps you to put sensor (and finger prick) readings into context.

It's a great metaphor. I was trying to think of a way to explain trends and could not have done any better that relating it to weather.
The metaphor also works with looking longer term than deciding whether you need a brolly, now.
I could look to see what the average temperature is for the second half of May. It does not mean it is that temperature now but it gives me an idea of what to expect.
If I leave now for two week long trip to Thailand, it will give me an idea whether I need to take a jacket or not.
In the same way, if my average BG 4 hours after breakfast (based on my last month of data ... which may be slightly higher or slightly lower than a finger prick) is higher than I want, my DSN and I may decided to increase my dose for breakfast.

 

[Sara Grice]

Having been involved in supporting students with their science experimental work where they may be comparing different treatments and they get odd results, when you go through what they have done it is apparent they have not kept their method consistent, they may have used a different instrument, added reagents in a different order, used a different incubation time or temperature so are introducing variables other than what it is they are comparing. Once they are consistent in their method then they can get meaningful results. If things look odd there is usually an explanation once you rule out sloppy methodology.

That's kind of what I've been trying to do, rule out the variables. But I guess I shouldn't have bothered. Sorry I'm just to wound up to have much of a convo anymore, as given what everyone is telling me it'd just the way things are....which just sucks cos this isn't something I feel like I can trust, but don't want to just fingerprick..cos people just won't admit it comes with alot of risk especially like me if your on set insulin, if you've got everything figured ou and know exactly whatnyoue body is going to do imnsure it's easier but I dunno how to do that without pretty good reliable info


so yeah I'm feeling pretty awful right now, so sorry if I was rude to anyone. I just don't know how I'm ever gonna cope

Edit: Thanks everyone tying to explain trends, so basicly it's just like a general guess as it what your level is? That feels vwry unscientific..Like you can make a relative guess as to what the weather will be on a curtain time of year in a curtain country, but how do you get an idea of what's normal or you without years of experience? Just starting out you don't have that yet. And I've had people with years at this still say it's hard to predict sometimes. So for a newbie..are trends something we just are expected to have a grasp off..then we haven't have much time to learn what's normal yet?

 

[rebrascora]

Also I want to ask one question, can you elaborate on when you said 4.5 compared to 7.8 is noteworthy but 11.3 to 14.8 isn't?? What's the difference they are both 3 mmol/ml apart and so if my sensor did sbow me at 4.5 then with how off it is right now it would be about 7.8.

The difference between 4.5 and 7.8 is 3.3mmols which is a very significant difference when you are in range because the Libre is factory calibrated to be at it's most accurate in range because that is where you should be spending most of your time and therefore this is where you want it to be most reliable. Above or below range you are advised to do a finger prick before taking any action ie, take a hypo treatment (unless you feel obviously hypo) or calculate a correction dose, because it is less reliable above and below range ie it will be further out. So your example of 11.3 and 14.8 is above range and the advice is to finger prick if you feel that you need to do a correction.... however you would not do a correction within 4 hours of a meal because your meal time (bolus) insulin would still be working. You are not doing corrections and you are not hypo so you don't need to worry about those high levels and how accurate they are, but I know from experience that the discrepancy between LIbre and finger prick reduces when you are in range and it is only a fair comparison if you test whilst levels are steady and in range to assess it's reliability, because that is where it is calibrated to be most reliable. BG meters are also further out at high levels, so there is no saying if it is your BG meter or your Libre which is out at that level. I am loath to suggest this because of your anxiety, but if you had 2 or even 3 different BG meters and tested the same drop of blood in the mid teens you will see a similar spread of results. None of these devices are accurate but they are less accurate the higher your levels are and at their best when levels are in range.

 

[Sara Grice]

The difference between 4.5 and 7.8 is 3.3mmols which is a very significant difference when you are in range because the Libre is factory calibrated to be at it's most accurate in range because that is where you should be spending most of your time and therefore this is where you want it to be most reliable. Above or below range you are advised to do a finger prick before taking any action ie, take a hypo treatment (unless you feel obviously hypo) or calculate a correction dose, because it is less reliable above and below range ie it will be further out. So your example of 11.3 and 14.8 is above range and the advice is to finger prick if you feel that you need to do a correction.... however you would not do a correction within 4 hours of a meal because your meal time (bolus) insulin would still be working. You are not doing corrections and you are not hypo so you don't need to worry about those high levels and how accurate they are, but I know from experience that the discrepancy between LIbre and finger prick reduces when you are in range and it is only a fair comparison if you test whilst levels are steady and in range to assess it's reliability, because that is where it is calibrated to be most reliable. BG meters are also further out at high levels, so there is no saying if it is your BG meter or your Libre which is out at that level. I am loath to suggest this because of your anxiety, but if you had 2 or even 3 different BG meters and tested the same drop of blood in the mid teens you will see a similar spread of results. None of these devices are accurate but they are less accurate the higher your levels are and at their best when levels are in range.

Oh OK I see what you mean...which is sort of why I was concerned this morning when it was still a bit off when I am usually the most steady (cos like..I do go up a bit in the morning but it's rare for me to go above 10)
It it was less off than it is when I go high

 

[rebrascora]

Yes, that's it and when you eventually get comfortable with levels in the 5s and 6s, you will see much less discrepancy between Libre and finger prick because both systems will be nearer to the actual value, as that is where they are calibrated to be most accurate. The higher your levels are, the more chance there is of the difference between them being bigger.

I am sure @everydayupsanddowns posted a red chart in one of your posts which shows the acceptable variation from the true value at different BG levels and if you looked at that closely, you will see that the variation is much smaller at low levels than at higher levels.

 

[Sara Grice]

Yes, that's it and when you eventually get comfortable with levels in the 5s and 6s, you will see much less discrepancy between Libre and finger prick because both systems will be nearer to the actual value, as that is where they are calibrated to be most accurate. The higher your levels are, the more chance there is of the difference between them being bigger.

I am sure @everydayupsanddowns posted a red chart in one of your posts which shows the acceptable variation from the true value at different BG levels and if you looked at that closely, you will see that the variation is much smaller at low levels than at higher levels.

I agree with that..t's just getting there when your struggling with trusting these things that's the problem if you can only trust a sensor best when you have good control..but your supposed to use the sensor to get said controll...its counterintuitive...

Whatever..I'm terid and brunt out and just wish this never happened to me

 

[helli]

I am sure @everydayupsanddowns posted a red chart in one of your posts which shows the acceptable variation from the true value at different BG levels and if you looked at that closely, you will see that the variation is much smaller at low levels than at higher levels.

This is the chart

The required accuracy is expressed as a percentage when BG is higher than 5.6mmol/l
With the example above of finger prick showing 14.8 and the Libre showing 11.3, this is within the "allowable" variation for a laboratory read BG of about 13.
As rebrascora mentioned, if your BG was in the 5s and 6s, the difference between the "allowable" upper and lower readings is much less but there is still scope for variations.

Remember, this has been good enough for many of us to calculate our insulin dose and stay alive without complications for 20 years or more. We do not need the laboratory accuracy.

 

[Inka]

Like you can make a relative guess as to what the weather will be on a curtain time of year in a curtain country, but how do you get an idea of what's normal or you without years of experience? Just starting out you don't have that yet.

You concentrate on staying safe @Sara Grice Not super-high not too low. You then begin to refine that very slowly by trying to reduce the level of your highest number, eg if your results are between 5 and 16, you try to tweak your insulin/routine to aim for your highest number being no higher than 15 most of the time, then after a while maybe aim for no higher than 14, etc. While you’re on fixed doses, you can’t tweak as much but you can still gather data and get a general feel for things.

don't want to just fingerprick..cos people just won't admit it comes with alot of risk especially like me if your on set insulin

People ‘won’t admit it’ because it’s not true. Fingerpricking is fine. As I said, you could even use the sensor only for Low alerts and fingerprick for blood sugar numbers. The biggest ‘risks’ on set insulin is mis-counting carbs. You’ve made little mention of your carb-counting, so I don’t know how you’re doing with that.

Finally - because I know you’re tired. Don’t overcomplicate things. The Libre shows you your blood sugar over 24hrs. It might, for example, show you go high and stay high for hours in the night. That’s useful info. It doesn’t matter precisely how high, so whether the Libre says 13, 14 or 16 doesn’t matter. If that happens for more than one night and appears to be a constant thing, that is something you can consider responding to.

The Libre is not the magic key to diabetes control. Nothing is. They are all tools to try to help us. There’s nothing that will guarantee great results all the time. Why? Because we’re trying to do a very hard job - be our own pancreas. Nobody is expecting perfection - not now, not in 5 years time. All you aim to do is to stay safe and to try to keep in range as much as you can. 70% in range counts as excellent control BTW.

 

[Lucyr]

Anyone know anymore and could elaborate?

You’re still panicking too much. Even if it affected your blood sugars in a meaningful way it wouldn’t affect the accuracy of the sensor vs the fingerprick.

The Vitamin C is well-known

Vitamin c only affects sensor readings if you’re taking more than 1000mg a day (libre 2+) or more than 500mg a day (libre 2). Given the RDA is 40mg a day it shouldn’t be an issue for people.

 

[Inka]

Yes, I know it’s only large amounts of vitamin C. I presumed Sara had read that in the info she referred to. It was the salicylic acid I was focussed on.

 

[Woodywoodpecker]

Oh OK I see what you mean...which is sort of why I was concerned this morning when it was still a bit off when I am usually the most steady (cos like..I do go up a bit in the morning but it's rare for me to go above 10)
It it was less off than it is when I go high

Sara grace I think you are like what I was in the beginning, over thinking everything. I’m a year in now and a lot more chilled with it all, don’t tend to prick my finger unless I get a low alarm. I was fixated on numbers mad if I went high or low. Went to hospital appointment and they said I was doing great, but in my mind I really thought I wasn’t. I have been carb counting and working out my dosage since week 2, very indecisive what was the right dose to take as didn’t want to go low or too high. I have realised it will never be perfect, if I go high now I don’t get mad at myself just say to myself what goes up must come down, if I go low just take glucose pills. Finding this forum has really helped me, we are all going through it together

 

[Sara Grice]

Sara grace I think you are like what I was in the beginning, over thinking everything. I’m a year in now and a lot more chilled with it all, don’t tend to prick my finger unless I get a low alarm. I was fixated on numbers mad if I went high or low. Went to hospital appointment and they said I was doing great, but in my mind I really thought I wasn’t. I have been carb counting and working out my dosage since week 2, very indecisive what was the right dose to take as didn’t want to go low or too high. I have realised it will never be perfect, if I go high now I don’t get mad at myself just say to myself what goes up must come down, if I go low just take glucose pills. Finding this forum has really helped me, we are all going through it together

What do you find reassurance and trust in then...cos thats what I'm struggling with most, I just want to feel safe and secure in what my levels actuly are...but that is impossible and it's hard to deal with......

 

[Woodywoodpecker]

What do you find reassurance and trust in then...cos thats what I'm struggling with most, I just want to feel safe and secure in what my levels actuly are...but that is impossible and it's hard to deal with......

I just trust my Libre, unless I have a low alarm then finger prick. Last night i miscalculated my dose for tea, went up to 14.3 didn’t finger prick as I knew it would come down, which it did. Believe me all this worrying is not doing you any good, in the beginning diabetes was all I thought about it was taking over my life, I was completely exhausted with it all. But as my doctor explained there will be times you go high and low and that’s ok, what is your TIR

 

[Sara Grice]

I just trust my Libre, unless I have a low alarm then finger prick. Last night i miscalculated my dose for tea, went up to 14.3 didn’t finger prick as I knew it would come down, which it did. Believe me all this worrying is not doing you any good, in the beginning diabetes was all I thought about it was taking over my life, I was completely exhausted with it all. But as my doctor explained there will be times you go high and low and that’s ok, what is your TIR

Tir is 55%

 

[Lucyr]

Yes, I know it’s only large amounts of vitamin C. I presumed Sara had read that in the info she referred to. It was the salicylic acid I was focussed on.

The salicylic acid isn’t referenced on the UK abbot page about libre 2 and 2+ though only on other countries pages eg the Saudi Arabia libre 1 page.

 

[Woodywoodpecker]

Tir is 55%

I’m wondering if you would benefit from doing your own carb counting, and working out your own dose off insulin, or is that too much for you just now. I was on fixed dose for 2 weeks, then started too do it myself, I found the fixed dose made me low after every meal. It’s all trial and error in the beginning

 

[Lucyr]

What do you find reassurance and trust in then

I just trust my libre. If it feels wrong I fingerprick but otherwise I rarely do. Last night it said 3.4 but I felt find and had been lying down so did a quick fingerprick, was about 6 so I just carried on as normal and libre soon leveled off at a similar bg in the 5s

 

[everydayupsanddowns]

This is the chart

For clarity - this chart is the allowable variation between 2 readings from the same BG meter, from 2 strips out of the same pot, and checking the same droplet of blood!

These are allowable variances from one fingerstick meter in order to meet ISO standards.

There isn’t a standard that sensors have to meet, but many aim to fall within a reasonably low MARD rating (mean absolute relative difference)

 

[Inka]

The salicylic acid isn’t referenced on the UK abbot page about libre 2 and 2+ though only on other countries pages eg the Saudi Arabia libre 1 page.

I meant Sara’s mentions of salicylic acid.

 

[Lucyr]

I meant Sara’s mentions of salicylic acid.

She’s not reading the UK site for the right type of libre sensor though?