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Incorrect readings on Libre 2

J

Jean Debby

Newbie
Messages
3
Type of diabetes
Type 1
Treatment type
Insulin
I've been using Libre 2 with an A5X reader (supplied by the hospital as my Motorola smartphone would not support the Freestyle app) since June 2022. Does anyone get suspect readings, particularly at nighttime? One of the the things I looked forward to was seeing my nighttime BG readings without having to wake up; however, the graph often shows significant dips which can be below 4, i.e hypo, then rising again without intervention. Someone suggested this may be because the sensor was on my left arm and I tend to sleep on my left side, so I have switched to putting the sensor on my right arm. All was going well until three nights ago when the low glucose alarm went off at 3am showing my BG as 2.9. I got up and five minutes later, it still read 2.9. As I had no hypo symptons, I used a test strip and lancet with my BG monitor and my BG read 9.0! I retested by pricking a different finger and this time the BG was 6.7. I tried scanning the sensor again and it came up with that annoying message saying sensor error and to rescan in 10 minutes, not what you want at 3:10am; however, after 10 minutes I scanned the sensor and it said 7.0.. I can't be having low glucose alarms in the night which wake my husband who has to wake me (his hearing is better than mine) so have taken to switching off the low-glucose alarms.
If I ring Abbott they say the A5X is not theirs. They have sent me a reader previously (I am now on my 2nd A5X reader) but it does not have the functionality of the A5X. Once you have started a sensor with one device, you cannot use another.
So do I switch from using the A5X to the Abbott reader or continue leaving off the low glucose alarm at night (and rely on hypo symptons to wake me if I have a hypo in the night, which is what used to happen before I had Lilbre2.
Or do I get a smartphone that supports the app?
Or try Dexcom, which is now also available on NHS?
 
I always used the reader and/or my phone to scan the Libre 2. People have varying opinions but my experience with the Libre as a whole (1&2) was that it was highly inaccurate no matter what I did. I ended up turning the alarms off due to it alerting me of the wrong blood sugar many times which was kind of the whole point of getting it to begin with and to always see my blood sugar and be notified of highs/lows. I don’t think using the correct monitor or a smartphone will make that much of a difference in my opinion.

I’ve never used Dexcom but I do know that it is very similar to the CGM I use now (Guardian). And with both of these you can enter a blood glucose reading to calibrate the sensor and keep it more within the correct range. I’ve personally had way less issues since I’ve been able to calibrate and couldn’t recommend a CGM that has that capability enough. If you can get it on the NHS I would say go for it.
 
Nicola M said:
I always used the reader and/or my phone to scan the Libre 2. People have varying opinions but my experience with the Libre as a whole (1&2) was that it was highly inaccurate no matter what I did. I ended up turning the alarms off due to it alerting me of the wrong blood sugar many times which was kind of the whole point of getting it to begin with and to always see my blood sugar and be notified of highs/lows. I don’t think using the correct monitor or a smartphone will make that much of a difference in my opinion.

I’ve never used Dexcom but I do know that it is very similar to the CGM I use now (Guardian). And with both of these you can enter a blood glucose reading to calibrate the sensor and keep it more within the correct range. I’ve personally had way less issues since I’ve been able to calibrate and couldn’t recommend a CGM that has that capability enough. If you can get it on the NHS I would say go for it.
Click to expand...
Would CGM mean having a pump? Hospital have suggested I might use a pump, but I am unsure.
 
Jean Debby said:
Would CGM mean having a pump? Hospital have suggested I might use a pump, but I am unsure.
Click to expand...
You don’t have to use one if you don’t want to, I know plenty of diabetics who use a CGM but don’t use a pump as they prefer pens. It’s down to the individual what they like and whether it will suit them. I’ve been on a pump for around 8 years now and would never go back to pens. It’s definitely an adjustment at first as you are connected to something 24/7 much like with a CGM. But you are able to fine tune your insulin needs a lot better with a pump. There are lots of pumps out there so I mean I’d ask what is available at your hospital and do your research on each one before making a decision.
 
The discussion about changing from Libre to a CGM is a total red herring. CGMs such as Dexcom use the same method of blood sugar calculation (reading interstitial fluid) as Libre. Many people call the Libre a CGM as it is continuously reading the glucose. Scanning only downloads the last 8 hours of data from the sensor's memory. It does not suddenly read that data from your arm.
Likewise, the type of reader will make little difference as it is downloading the same data.

@Jean Debby you only mentioned inaccuracies at night which certainly suggests compression lows. Whilst you may favour one side for sleeping, we all love about at night so could trigger these false lows. Do you test the accuracy of the Libre during the day to confirm the overall accuracy? I would jump to no conclusion until you have.
If you find your sensor is inaccurate during the day, contact Abbott with proof and they will replace your sensor. If it is fine during the day, consider placing your sensor somewhere else. For example, I put mine high up on my arm and slightly under it. I never apply pressure there when asleep.
Finally, you say you checked 5 or 10 minutes later. Why are you not checking immediately? All lows from all CGMs should be checked with finger pricks as soon as possible. You should have diabetes kit with you at all times including next to the bed. You don't have to get up to wash your hands before testing. Unless you have been eating in bed, you will not have sugar residue on your finger tips
 
Last edited by a moderator:
Jean Debby said:
I've been using Libre 2 with an A5X reader (supplied by the hospital as my Motorola smartphone would not support the Freestyle app) since June 2022. Does anyone get suspect readings, particularly at nighttime? One of the the things I looked forward to was seeing my nighttime BG readings without having to wake up; however, the graph often shows significant dips which can be below 4, i.e hypo, then rising again without intervention. Someone suggested this may be because the sensor was on my left arm and I tend to sleep on my left side, so I have switched to putting the sensor on my right arm. All was going well until three nights ago when the low glucose alarm went off at 3am showing my BG as 2.9. I got up and five minutes later, it still read 2.9. As I had no hypo symptons, I used a test strip and lancet with my BG monitor and my BG read 9.0! I retested by pricking a different finger and this time the BG was 6.7. I tried scanning the sensor again and it came up with that annoying message saying sensor error and to rescan in 10 minutes, not what you want at 3:10am; however, after 10 minutes I scanned the sensor and it said 7.0.. I can't be having low glucose alarms in the night which wake my husband who has to wake me (his hearing is better than mine) so have taken to switching off the low-glucose alarms.
If I ring Abbott they say the A5X is not theirs. They have sent me a reader previously (I am now on my 2nd A5X reader) but it does not have the functionality of the A5X. Once you have started a sensor with one device, you cannot use another.
So do I switch from using the A5X to the Abbott reader or continue leaving off the low glucose alarm at night (and rely on hypo symptons to wake me if I have a hypo in the night, which is what used to happen before I had Lilbre2.
Or do I get a smartphone that supports the app?
Or try Dexcom, which is now also available on NHS?
Click to expand...
Mine went off 4 times one night saying it was below 4, I felt ok so did nothing checked again 10 mins later it was 6, each time, I have had that a few times now, plus no end of errors messages, mine is now giving the wrong time that I have tested,
 
Jean board said:
Mine went off 4 times one night saying it was below 4, I felt ok so did nothing checked again 10 mins later it was 6, each time, I have had that a few times now, plus no end of errors messages, mine is now giving the wrong time that I have tested,
Click to expand...
That sounds like compression lows as I mentioned above.
 
Two things I have noticed with the Libre that may help address your concerns.

If the low sugar alarm goes and the reading is more than .2 or .3 below the trigger point - say it's set for 4.3 and reads 3.5, it's probably a false reading and needs to be checked with finger prick test. It is very unlikely that your BG is changing so rapidly it moves from above the trigger point to well below between updates, particularly at night.

The other is when there is rapid change from going down to up or vice versa the scanner will shut down and give the "gone fishin', back in 10" error for a few minutes as it trys to recover and make sense of what it was reading two mins ago against what it's reading now, particularly after a compression low or over enthusiastically treated hypo.
 
"...leaving off the low glucose alarm at night (and rely on hypo symptons to wake me if I have a hypo in the night, which is what used to happen before I had Lilbre2.
Or do I get a smartphone that supports the app?
Or try Dexcom, which is now also available on NHS?"

Only leave off the alarm if you are confident you have the hypo awareness to wake you before you need help to treat a real hypo. After over two years on a CGM I'm not sure if I have or not. Plus if you have a compression low and it stays like that for an extended period, even though it's a false reading, it will mess up your log and time in range on your app or reader. Relieve the pressure and the log and graph will correct itself and not show any time in the hypo range.

If your reader works and you wouldn't otherwise change the phone, why bother...except for the convenience of only having to carry one device.

Check your existing phone can support the Dexcom app before changing CGMs. Otherwise, with no reader or phone app Dexcom will be useless.
 
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