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11 Posts
Discussion Starter · #1 ·
Here in the north east we have had a heat wave (in the 90's).
Recently I noticed my low glucose alarm was going off quite often, almost exclusively when I was driving in my hot car.
I thought that was odd, so I paid more attention to my freestyle libre readings before jumped into my hot car.

I found no information about this problem on the internet.

Here was what I documented:
2:28 :Before I hopped in my car, my glucose read 130 mg/dl and going up
12 minutes later driving in my hot car my glucose read 85 mg/dl and was going down.
That was a drop of 45 mg/dl in 12 minutes
Another time:
2:04: before I hopped in my car, my glucose was 114 mg/dl
7 minutes later in my hot car my glucose read car 74 mg/dl
That was a drop of 40 mg/dl in 12 minutes

Unfortunately I did not have my blood glucose meter on me to accurately check my sugars.

My sugar went down a crazy significant amount every time I was driving in my hot car (waiting for my A/C to kick in).

I believe this is a flaw of the Freestyle Libre and was wondering if anyone else happen to notice the same issues?

11 Posts
Discussion Starter · #5 ·
Thank you all for your input!
"Freestyle folks list 36°F and 82°F as the storage temperature range of the sensor kit ".
That would explain why the sensor is acting so quirky.
I am now paying little or no attention to the frequent low glucose alerts while I am in the hot car.

@Lee_Bo the Freestyle Libre 2 alerts come in very handy. I often have low blood sugars at night while I am sleeping
and I set it to 75 (way before it gets to be really low).

11 Posts
Discussion Starter · #9 ·
Thanks for the reply. I too have found that my night time lows are often "off". My low glucose alarm (set to 75 mg/dl) was going off 3 times a night. One night after a alert on a low 74 mg/dl I tested on my blood glucose monitor.
I found the reading was much higher (149 mg/dl) and not at all the "low" reported on the freestyle libre app on my iPhone.
When I tested again 5 minutes later on my freestyle libre app on my phone and the number was much higher (130 mg/dl- note: I did not eat a thing).
I have been testing using both the libre app on my iPhone and my blood glucose meter (BGM) and found that the libre can be spot on, or way off.
I am sure my A1c is going to be higher next time I go to the lab, because I was assuming the freestyle libre was accurate.
But my assumption was not correct.
I believe currently libre is compatible with iPhone 7 and newer and the newest software upgrade of IOS 15.3.
My current IOS is 15.6.1, which I have set to automatically upgrade (not sure if this is the reason for the disparity).

I wish libre would allow use of both the app on your phone and the libre reader at the same time.
Since I could check my sugars on both, since the reader is not subject to software upgrade that may compromise accurate readings.
I think I may switch to the reader on my next sensor to see if it is more accurate (not as convenient as my iPhone).

My advise would be to always double check your numbers on a BGM when reading low, before reaching for the Ice cream or a sweet snack.:rolleyes:

FYI: I did speak to a libre representative and he stated the libre app works best between 50° F and 100° F.

I want to also mention sugarmds youtube videos have a ton of great information for diabetics.
Here is the link

11 Posts
Discussion Starter · #11 ·
I wanted to follow up from my post on Aug 26, 2022
I have been using my Freestyle Libre READER, instead of the Libre app on my iphone and have found that that the discrepancy on my readings to be much better and not so extreme.
Within the last few days I have compared my CMG (Freestyle Libre READER) with my (BGM-Blood Glucose monitor) readings.

Here are the results
I have completed the comparison 20 times
Of the 20 times the discrepancy were no more then 20 mg/dl ( + or -) difference from the CMG (READER) to the BGM.
13 of the 20 times, the discrepancy was 10 mg/dl or less ( + or -).
7 of the 20 times, the discrepancy was between 11 mg/dl and 20 mg/dl (+ or -).
Not sure if the problem was the sensor? Or the Libre Iphone app (since my IOS was not listed as part of the compatibility range)?

Although the the READER is not as convenient as using the Libre App on my Iphone.
I am happy to trade accuracy with convenience.

Did you know that Coffee, sweeteners and Nasal sprays can raise your blood sugar?
I have started to cut down and eliminate all 3, and my sugars have been better.

Hope this helps!!
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