Freestyle libre

[Ann_W]

Hi everyone, I’ve been type 2 diabetic for 10 years. Unfortunately, my control isn’t what it was (I was warned this might happen) I’ve always had to self fund monitors. We’ve moved 4 times in 5 years and am with my best diabetes nurse yet. 1st thing she did was give me a monitor and encourage me to apply for a free freestyle libre which came today. I’m doing a week long log for her but it’s looking like I’m going to need insulin and she can prescribe me the libre if we decide that is the route for me.
To come to my question, the readings on the libre are about 2 mmol higher than the finger prick ones - is this normal? I’m checking them against each other atm. I’ll discuss with the nurse tomorrow but I’m just curious if this is common.

 

[mariavontrapp]

Hi Ann, I use the Libre and yes, sometimes the numbers don't match. My last one was almost perfect, but my current one is about 1.2mmol out on each reading. You need to remember there is a lag on the cgm compared to the finger prick test, so there will be more variation when your glucose is on the move (for example going up after a meal) compared to when it's just ticking along.

 

[Ann_W]

Hi Ann, I use the Libre and yes, sometimes the numbers don't match. My last one was almost perfect, but my current one is about 1.2mmol out on each reading. You need to remember there is a lag on the cgm compared to the finger prick test, so there will be more variation when your glucose is on the move (for example going up after a meal) compared to when it's just ticking along.

Thank you for this. At present, there’s a good 2 mmol difference between the 2 when they are measured at the same time. The finger prick monitor was given to me by the nurse so I’m confident with that. Thanks for your reply, I want to make the libre work for me so that I don’t do what I did yesterday (before I got the libre) and go out without the monitor and end up cursing under my breath, lol. I wouldn’t have been so concerned normally except for keeping these results for the nurse. Although if I do go on insulin, that’ll be a whole other story….

 

[Introverted_And_Proud]

Hello Ann. Fellow Freestyle Libre user here.

Just wanted to add on to what mariavontrapp said: upon activating the sensor, its readings can be quite sporadic within the first 48 hours. Despite the one hour warm up, some people (myself included) have found that it can take a little longer for the sensor to adjust. So, it can be normal for sensor readings to vary quite a bit from the finger prick for the first two days anyways.

Some of us have found that activating the sensors one or two days after applying them helps a little bit with accuracy. Sometimes our bodies need a bit of extra time to settle with the sensor because it didn't react well to having a foreign object jabbed into it. Lol. XD Might be worth a try for future sensors.

 

[Jaylee]

Hi,

The CGM reads intestinal fluid with a probe under the skin. (Or the BG in it.)
Glucose in the blood from a finger prick for me is always ahead slightly of the Libre.
Even with low blood sugars as a T1 on insulin the representation of the Libre can lag behind on recovery. Though the recent sensor algorythms can give me a 10 minute heads up on an impending low. (The brain gets the sugar first.?)
Hence why I double check with a meter.

 

[Ann_W]

Hello Ann. Fellow Freestyle Libre user here.

Just wanted to add on to what mariavontrapp said: upon activating the sensor, its readings can be quite sporadic within the first 48 hours. Despite the one hour warm up, some people (myself included) have found that it can take a little longer for the sensor to adjust. So, it can be normal for sensor readings to vary quite a bit from the finger prick for the first two days anyways.

Some of us have found that activating the sensors one or two days after applying them helps a little bit with accuracy. Sometimes our bodies need a bit of extra time to settle with the sensor because it didn't react well to having a foreign object jabbed into it. Lol. XD Might be worth a try for future sensors.

Thank you for these tips, much appreciated them

 

[Ann_W]

Hi,

The CGM reads intestinal fluid with a probe under the skin. (Or the BG in it.)
Glucose in the blood from a finger prick for me is always ahead slightly of the Libre.
Even with low blood sugars as a T1 on insulin the representation of the Libre can lag behind on recovery. Though the recent sensor algorythms can give me a 10 minute heads up on an impending low. (The brain gets the sugar first.?)
Hence why I double check with a meter.

Thanks Jaylee, all this knowledge is so useful

 

[Jaylee]

Thanks Jaylee, all this knowledge is so useful

Good luck with getting them prescribed.
You’ll soon work out how they work for you…

Personally. Mine works from fitting. I don’t need to wait 2 flipping days for a sensible result.
But it doesn’t go amiss to check against the meter.

 

[Ann_W]

Good luck with getting them prescribed.
You’ll soon work out how they work for you…

Personally. Mine works from fitting. I don’t need to wait 2 flipping days for a sensible result.
But it doesn’t go amiss to check against the meter.

The nurse has said she can prescribe them if I need insulin so we’ll see. I’ll be checking against the meter until I’m confident with it ans even then I agree it doesn’t go amiss to check now and again

 

[Introverted_And_Proud]

The nurse has said she can prescribe them if I need insulin so we’ll see. I’ll be checking against the meter until I’m confident with it ans even then I agree it doesn’t go amiss to check now and again

It is usually advised for you to double check any low or high blood sugar sensor readings against your glucose meter readings before making any treatment decisions. Or any sensor readings you might generally be unsure about. So, it is best to always have your glucose meter with you just in case something goes wrong with the sensors.

 

[Ann_W]

It is usually advised for you to double check any low or high blood sugar sensor readings against your glucose meter readings before making any treatment decisions. Or any sensor readings you might generally be unsure about. So, it is best to always have your glucose meter with you just in case something goes wrong with the sensors.

It makes complete sense to do that , thank you

 

[grantg]

its worth noting dexcom1 offer a free trial as well https://www.dexcom.com/en-GB/one-plus-campaign-sample multiple insulin injections a day for type2 before nhs may supply. i tried to get my mum to get cgm prescribed to no avail even though she had 2 injections per day and was experiencing multiple hypo's a day guess it depends on DSN / consultant alongside rules.

for libre sensors if consistantly a lot of difference between readings its worth calling abbot who will usually send out a replacement sensor that way it wont cost the nhs or yourself (if have to self fund)

for me the sensor consistantly reads a fair bit lower out by a few mmol.

I'd try experiment a lot with various types of foods keeping a careful diary so if don't qualify for libre you can use the free trial time to the fullest advantage. notedown meals / carbs and how quickly sugars spike / come down.

 

[Ann_W]

its worth noting dexcom1 offer a free trial as well https://www.dexcom.com/en-GB/one-plus-campaign-sample multiple insulin injections a day for type2 before nhs may supply. i tried to get my mum to get cgm prescribed to no avail even though she had 2 injections per day and was experiencing multiple hypo's a day guess it depends on DSN / consultant alongside rules.

for libre sensors if consistantly a lot of difference between readings its worth calling abbot who will usually send out a replacement sensor that way it wont cost the nhs or yourself (if have to self fund)

for me the sensor consistantly reads a fair bit lower out by a few mmol.

I'd try experiment a lot with various types of foods keeping a careful diary so if don't qualify for libre you can use the free trial time to the fullest advantage. notedown meals / carbs and how quickly sugars spike / come down.

This is what I’m doing at the moment and it can be a bit of an eye opener. Yesterday I had a small piece of thin base pizzaI tested before and two hours after and got the result I pretty much expected. What I didn’t expect though was watching the numbers continue to rise on the libre for about another hour so that was interesting and enlightening. I tried the free dexcom a few weeks ago and it packed in after 5 days. Didn’t think to ring dexcom about it though.

 

[ChrisT2]

I cannot agree more with the advantages of a CGM in trying to manage our condition. I tend to use a self funded Libre and also regularly finger prick. Why i still do both I cant explain but maybe it's a trust thing. Like most my finger readings are around 2mmols higher above the same reading on the Libre. However having just had my annual HbA1c blood test the hospital readings almost match the Libre estimated HbA1c which I will take as a bonus. This may be a fluke and I will have to wait another year before I can make the same comparison but as the Libre can be used in tandem with insulin pumps (for type 1s specifically) which has to be accurate and critical I am happy to go with the CGM technology. Either way both methods of testing are extremely useful but the Libre gives concise pictures in almost real time of what your blood sugar is doing whether, eating, exercising or just plain sleeping. I can understand pictures much more than plain numbers these days.
BTW other CGMs are available and I can only comment on Libre which I used after the free 2 week trial. Good luck in whatever choice works best for you.

 

[Melgar]

The more I read members varying experiences with Libre s accuracy the more I think our bodies vary considerably in how fast or how quickly glucose finds its way into the interstitial fluid or even how our body reacts to the filament penetrating our skin.

My own experiences with Libra is the same as yours @ChrisT2 . My Libre values are always lower than my finger prick figures, even given Libra's lag in glucose readings, but only around the 'normal range' . Outside of that range the accuracy of the Libre diminishes. Interestingly, my finger prick device's readings were lower than the pharmacy device when I asked them to compare my device with theirs. Of course, we have to consider the allowable error of 15%+/-. Only the lab device, which I presume is calibrated to higher level of accuracy.

We miss so much with the standard before and two hours after a meal. The highs and the lows between those figures.

Also my estimated Libre HbA1c is always lower , sometimes the difference is significant, than the lab run HbA1c results.

 

[mariavontrapp]

It is usually advised for you to double check any low or high blood sugar sensor readings against your glucose meter readings before making any treatment decisions. Or any sensor readings you might generally be unsure about. So, it is best to always have your glucose meter with you just in case something goes wrong with the sensors.

Hi everyone, I’ve been type 2 diabetic for 10 years. Unfortunately, my control isn’t what it was (I was warned this might happen) I’ve always had to self fund monitors. We’ve moved 4 times in 5 years and am with my best diabetes nurse yet. 1st thing she did was give me a monitor and encourage me to apply for a free freestyle libre which came today. I’m doing a week long log for her but it’s looking like I’m going to need insulin and she can prescribe me the libre if we decide that is the route for me.
To come to my question, the readings on the libre are about 2 mmol higher than the finger prick ones - is this normal? I’m checking them against each other atm. I’ll discuss with the nurse tomorrow but I’m just curious if this is common.

By the way, I'm a Type 2 on insulin but the nurse won't prescribe a cgm for me. I wonder if different areas of the country have different rules?

 

[TomLH]

Hi everyone, I’ve been type 2 diabetic for 10 years. Unfortunately, my control isn’t what it was (I was warned this might happen) I’ve always had to self fund monitors. We’ve moved 4 times in 5 years and am with my best diabetes nurse yet. 1st thing she did was give me a monitor and encourage me to apply for a free freestyle libre which came today. I’m doing a week long log for her but it’s looking like I’m going to need insulin and she can prescribe me the libre if we decide that is the route for me.
To come to my question, the readings on the libre are about 2 mmol higher than the finger prick ones - is this normal? I’m checking them against each other atm. I’ll discuss with the nurse tomorrow but I’m just curious if this is common.

Hi, I also use the Libre2 sensor and was advised that the sensor always produces a higher reading than a finger prick test. I believe this is because the sensor is obtaining a reading in a different way/different part of the body and apparently this is quite normal. A technician at Abbott Laboratories advised me to take the finger prick test about 15 minutes or so after the Libre2 reading, as they will become more aligned.
Obviously, you should discuss this in more detail with your nurse, but this is a brief summary of my own experiences. Hope it is of help.

 

[Introverted_And_Proud]

I cannot agree more with the advantages of a CGM in trying to manage our condition. I tend to use a self funded Libre and also regularly finger prick. Why i still do both I cant explain but maybe it's a trust thing. Like most my finger readings are around 2mmols higher above the same reading on the Libre. However having just had my annual HbA1c blood test the hospital readings almost match the Libre estimated HbA1c which I will take as a bonus. This may be a fluke and I will have to wait another year before I can make the same comparison but as the Libre can be used in tandem with insulin pumps (for type 1s specifically) which has to be accurate and critical I am happy to go with the CGM technology. Either way both methods of testing are extremely useful but the Libre gives concise pictures in almost real time of what your blood sugar is doing whether, eating, exercising or just plain sleeping. I can understand pictures much more than plain numbers these days.
BTW other CGMs are available and I can only comment on Libre which I used after the free 2 week trial. Good luck in whatever choice works best for you.

I don't blame you for still finger pricking alongside the sensors. I still do finger prick tests with my meals and before bed and then log it in the LibreLink logbook with the sensor reading at the time. My sensors are frequently hit and miss, so I'm lucky if I manage to wear a sensor for the full 14 days (15 now; recently got switched to Libre 2 Plus sensors). Also, because I have to add correction doses to my bolus meal injections, and my sensors' behaviours can be erratic, it's difficult for me to inject properly without accidentally injecting too much or too little. So, it's always been safer for me to inject per my BG reading rather than the sensor, despite Abbott's claims it's fine to bolus per the sensor readings. Really, I only rely on the sensors to track the behaviour of my blood sugars with my food and insulin more than anything, which is why I agree with you: both the Libre and glucose meters are useful in their own ways, though the Libre is definitely more informative when it works. XD

 

[Hopeful34]

Hi, I also use the Libre2 sensor and was advised that the sensor always produces a higher reading than a finger prick test

I used Libre 1 and 2 for quite a while before getting a tandem pump, and had a mixture of lower, spot on, and higher than blood tests results.

 

[Ann_W]

Thank you all very much for your replies. I am going on one dose of insulin per night at the moment and we’ll take it from there so I can’t get the libre prescribed unless I go on to need at least one more dose per day but I think I’ll self fund another couple and use them as educators. You’ve all given me some great advice here and I’m very grateful to you