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.