Would you continue to use Blood Glucose Monitor OR Freestyle Libre 2 Sensor?

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s14ali

s14ali

Active Member
Relationship to Diabetes
Type 1
I received the Libre 2 sensor from NHS for the first time yesterday but I am really concerned.

Firstly, I acknowledged that it is normal about the difference between Sensor Glucose (Interstitial fluid) and Blood Glucose, according to Abbot website and manual instruction. However, I didn't realise that the reading is quite big gap, eg. 10mmol/L (SG) and 8mmol/L (BG). It seems always 2-3mmol/L more or less. Abbot said that reading is accurate and painless. Well, I feel slightly pain when I move my arm up and sometimes side.

I read few posts about the issues and people have the same problems. Blood Glucose Monitor is much more accurate as I can feel it. I don't think I would continue to use a sensor or shall I try it again next time? I really want a sensor rather than multi-testing kits.

As I know it's my first time with a sensor but I assume that I placed it on back upper arm incorrectly or it could be misread or not scan it properly through the clothes. Maybe try a new sensor could be work?
 
CGMs like Libre are not replacements for finger pricking. They provide data and trends between individual readings.
CGMs also have limitations which have been mentioned many many times. For example, many of us find our body takes some time (up to 48 hours) familiarising itself with the alien object in our arm and, during this period, it may be unreliable. So if you have only just started using the sensor, this may be the reason why your readings are so far out.
It is also worth bearing in mind that the accuracy is expressed as a percentage. CGMs and finger prick meters are 15% accurate. If your "true" reading is 9, a glucose meter can report anything between 7.6 and 10.3.
 
Bet you started the sensor more or less as soon as you inserted it - any number of us have found they usually become more accurate in line with our BG meters if we insert the new one the day before the current one expires so the new one gets a bit of time to get used to our own body before starting it - hence tomorrow when the old one runs out, we can start the new one more or less straight away.

My current one was pretty much cock on for a week or more but then went haywire on and off, sometimes it wasn't, sometimes it was and today, ended itself with no prior warning - just refused to scan and hen - and still - won't and now at least telling me 'No sensor detected'.

I've never been able to trust them for boluses or correction doses because I've rarely had one after the other be accurate so I simply use it much more for trends - eg has the jab I had for lunch working by now? rather than wanting to know what my BG actually is right now this very minute. Also, very useful for basal insulin testing purposes.
 
I absolutely love Libre and it works brilliantly for me within it's limitations but you have to accept both that the reading it gives you and the reading you get from a finger prick are not the same and neither of them are absolutely accurate. A finger prick has the last say if there is any concern over a Libre reading and generally Libre reads about 1mmol below BG readings most of the time for me, so if Libre says 3.1 I am likely nearer 4.1 but 1 jelly baby will not do me any harm in that situation to raise my levels into the 5s, although I have my alarm set at 4.2 so I rarely get readings below 4 now.

I usually check each sensor a couple of times in the first few days against a finger prick and I wait until my levels are nice and stable in the 5s or 6s for at least half an hour to do those checks. If it is out by more than 1.5mmols I will probably do a few more checks to make sure that is consistent and adjust my calculations accordingly, but under 2mmols out is still perfectly workable. I have just checked back and I have finger pricked 5 times in the last 11 days of this sensors life. That is a couple of checks in the first few days as mentioned above and then a hypo which needed a couple of strips and one other test when I was borderline according to Libre and needed to drive. If Libre shows me 3.8 when I am about to drive and I don't feel hypo, I do a quick finger prick check. If BG is above 4 I eat carbs and drive. If below 4 with a finger prick, I am of course grounded.
 
Oh yes, I too apply the sensor about 12 hours before activating it, to give it time to bed in, so one night a fortnight I have 2 sensors on overnight.

If you can feel it nipping slightly, then either you nicked a nerve during insertion, which should wear off after a few days or you have a hair caught in the adhesive which is pulling as you move your arm. I believe some people (men usually) find it best to shave the site before applying the sensor.
 
Oh gosh yes, even through my thickest winter coats with fleece on underneath, there is no problem scanning through clothing although I am led to believe that the Libre reader which I use, is much better at picking up the sensor than the phone app. which can require you to be much more precise about holding the phone over the sensor in just the right position.
 
You really can drive yourself mad trying to compare between the Libre and finger prick testing. For me, once my BG is stable for an hour or so I do find that the Libre can be around 0.5 or less difference from the BG reading. Other times it can be out by 1 or more either side of BG, but there is always a lag between ISF that the Libre reads and actual BG so I accept that. I use the Libre for making bolus decisions and have not had any issues, in fact my DSN actually said to do so. I think the main value of the Libre is to see the trends and effects of different foods, etc. rather than being too concerned with absolute BG values, the overall goal is to improve your time in range which in turn will result in better HbA1c figures.

As to the slight pain, especially when moving your arm, I’ve had that on one sensor so far and it turned out to be a trapped hair caught on the adhesive which pulled/tugged when I moved my arm. I managed to spot it close to the edge of the patch and pulled it free which made the tugging issue go away. I am on my 18th sensor now and I can say that other than that one, I do not feel them nor are aware of them even being attached to my arm. Sometimes you may be aware of something on your arm on the first day but after that you shouldn’t notice it.

As others have said, it will scan through even thick coats and layers of clothing. I use an iPhone and it does have to be positioned fairly accurately over it, but other than that it reads just fine. As long as it scans and gets a reading it will be fine and as accurate as reading ISF can be against BG.

I really would encourage you to persevere with it as the benefits are well worthwhile.
 
I value the information from both glucose sensors and fingersticks.

I would always expect to use both - mostly being able to rely on sensor glucose values, but having the option of capillary blood glucose where that is helpful.

Some Libre sensors read a bit weirdly for me, and sensors are often a bit wonky in the first 24 hours, but with Dexcom G6 I’m happy to use sensor values for dose calculations the majority of the time 🙂
 
Hi. I always shave before fitting the sensor and use an iso-propanol wipe. I use the fleshy part of the upper arm on the side. I fold my arm to see where the fleshy part is and mark it with a pen.
 
To answer some of your posts:
  • I use a Libre reader to scan a sensor, not phone.
  • I followed the instruction, I removed the hair, checked no mark/unusual skins and wiped it with medical alcohol wipe before applied it.
  • I forgot to mention about my arm, my flesh is quite thin, no muscle. Does it affect the reading? Maybe try on different position.
  • I think I should place it slightly higher than original position to avoid the injury during arm movement.
  • I do know that sensor isn't replace the finger-prick and hopefully a sensor will familiarise my body in next few days to read the blood level properly that it won't show the big gap. However, I understand the trending arrow/Interstitial Fluid difference but it cannot truly tell if the Blood Glucose is high or low. Let's say that you take only Libre reader (without finger-prick) to work or outdoor activity, you scan it and say 8.0mml/L, so you guess that Blood Glucose would be 6.5mml/L but actually 9.5mml/L. If sensor seem go well onto my skin overtime and it shows the very small difference then I won't have any problem.
 
To me, the important thing about the Libre is being able to put the spot reading into context by looking at the graph. This tells me if my blood glucose is falling rapidly, or rising, or is steady, and I take that into consideration when deciding on my insulin. I find it more helpful than a test from a fingerprick which tells me nothing except that my blood glucose was a certain number at a short moment in time.
 
I really only use mine for patterns and trends. I too struggled with the inaccuracy to begin with. I’m guessing mine is pretty much always reading 2 points lower as my predicted hba1c on libre is currently 33 mmol which I was very happy about. Hba1c done last Saturday says I’m at 41. Biggest gap I’ve ever had.
 
rebrascora said:
Oh yes, I too apply the sensor about 12 hours before activating it, to give it time to bed in, so one night a fortnight I have 2 sensors on overnight.

If you can feel it nipping slightly, then either you nicked a nerve during insertion, which should wear off after a few days or you have a hair caught in the adhesive which is pulling as you move your arm. I believe some people (men usually) find it best to shave the site before applying the sensor.
Click to expand...
When you put the second sensor on, do you also need to start the activation with the phone? Or just stick it in? Sorry I'm sure that will be a dumb question once I have done it once!

Edit: reason I ask is that I'm now 12 hrs off the end of my first Libre 2 and thinking I might as well copy the experts' homework...
 
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Toooldfortype1 said:
When you put the second sensor on, do you also need to start the activation with the phone? Or just stick it in? Sorry I'm sure that will be a dumb question once I have done it once!

Edit: reason I ask is that I'm now 12 hrs off the end of my first Libre 2 and thinking I might as well copy the experts' homework...
Click to expand...
You can put the new sensor on, and ignore it and carry on using the old sensor until it runs out. If you accidentally scan the new sensor while the old one is still active, the screen will show the message 'Do you want to start a new sensor?' If you say no, you can then scan the old one. If you say yes, it will end the old sensor and start the one hour warm up period for the new one. (NB there will always be an hour between the old and new when you can’t scan,)
 
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