• Guest - w'd love to know what you think about the forum! Take the 2025 Survey »

Glucometer

F

fantastic9888

Well-Known Member
Messages
107
Type of diabetes
Treatment type
Insulin
Hi all. Where I live is cool in the morning. I refer to my bedroom. When I check sugars in bed in the morning, they could be around 8.00mmol. but when I place glucometer under the bedclothes, I can get a reading of 2.00mmol less. So my question is. Which reading is the real reading? Cheers Kevin. My room is the morning is around 12°C. Glucometer feels cold to touch
 
Spooky! I was just wondering why my readings have been up recently and realised (literally 10 minutes ago) that I haven’t been putting my test kit under my pillow as usual. I am currently testing with 2 different kits due to not trusting one of them, and having both kits under my pillow was too uncomfortable. My bedroom is also 11-12 deg C.

I have noticed the readings are much lower when the kits are warmer, but as to which reading is correct, I have no idea. My Libre CGM is generally several points higher and I can actually watch it rise as I prepare the meters. So I ignore that reading.
 
Spooky indeed. Never heard on a Glucometer giving lower readings when it's warm and a 2 mmol/L difference is annoying.
Looks like the only way to sort it out is to calibrate it with BG control solutions - you can get these from Amazon.

Btw - don't expect a Glucometer and a CGM to be the same because a Glucometer measures blood glucose and a CGM is measures interstitial fluid glucose - depending on your activity, these can be up to 2 mmol/L out with the CGM usually recording lower.
 
I only use the CGM as a rough guide, because I am fully aware of how it works.

This morning’s readings, after putting the GlucoNavii kit under my pillow and leaving the CodeFree on my bedside table were:
GlucoNavii 4.3
CodeFree 6.8

2nd reading immediately thereafter, different finger, same blood drop.
GlucoNavii 4.0
CodeFree 6.4
 

You DONT calibrate with control solutions.. the control solution simply verifies that the meter is working with range.. if the meter tests within the range on the side of the test strip pot it’s considered accurate

But no calibration happens
 
Recently, I purchased a monitor locally for a diabetic friend. When recorded under the same conditions, the results from the two kits, hers and mine, were within 0.1 mmol of each other.

If in doubt, a control solution to test the functionality of your meter and test strips is available from your local pharmacy. If stored properly, they will keep for 12 weeks after opening and some last much longer.
 

However they can be quite different! The can be upto 15% out. When you look at a control solution test.y contour on a mid range test is considered OK if between 6.3 and 7.9. Same meter brand will often give very similar results but test with 2 different brand and that can be quite different

These are not lab grade testing kit which is why there can be quite big variances

And again control solution on confirms does not calibrate
 
I angree about the control solution being verification and nothing to do with calibration. I have already checked with the solution.
Day 2 of the experiment:
Libre 6.7
GlucoNavii (under pillow) 4.8
CodeFree 6.7

Incidentally, during the course of the day, both meters read within 0.5 of each other. It’s only the early morning readings, after a night in cold conditions, that there appears to be a discrepancy. This is what the OP @fantastic9888 is querying, as they seem to be having similar issues.
 
Are you using test strips at the same temperature as the meter? If you put a cold strip in a warm meter or vice versa, that could be having an effect on the enzyme reaction on the strip.
 
@Antje77 SNAP! I have just written that in the other forum. Copying and pasting here:

Day 3 of temperature experiment.
Libre 6.7
GlucoNavii 4.3
CodeFree 6.8

After 3 days of the GN showing readings in the 4tress, rather than the stickies or hive, I am going to switch kits and bring the CodeFree in out of the cold instead tonight.

You are a mind reader @Antje77
 
Jasmin2000 said:
Are you using test strips at the same temperature as the meter? If you put a cold strip in a warm meter or vice versa, that could be having an effect on the enzyme reaction on the strip.
Click to expand...
I put my entire kit under my pillow, so meter, strips and finger poker. I suspect it is the strips’ temperature that makes the difference, as the manufacturers say to store the strips at 11 deg or above. It definitely drops below 11 during the night as I can see from my Hive graphs the heating kicks in several times at regular intervals to boost it to 12 deg.
 
aylalake said:
I suspect it is the strips’ temperature that makes the difference, as the manufacturers say to store the strips at 11 deg or above.
Click to expand...
Oh my. Must check the leaflet with my strips, my house is below 11 deg most of the day during winter. I haven't noticed any obvious differences testing at home or in warmer environments, but I haven't looked for them either.
I have read the leaflet with my meter, which says it works at 4 deg or above, and I have had error codes when I tried to use it below (easily solved by putting the meter under your arm for a minute or two) but I've never read the leaflet with my teststrips, assuming it would be the same as the meter.

Why would they sell a meter that can be used at 4 deg but with teststrips that can't?
 
I have just checked and nowhere does it say 11 deg!! I have no idea where I saw that! They both say (as did you) 4 deg C minimum. How very odd. I was totally convinced about the storage temperature. Apologies for misleading you and probably others.

Anyway, this morning’s results (after a square of 85% chocolate at 10pm):

Libre 8.1
GlucoNavii (left out in the cold) 8.9
CodeFree (tucked up in the warmth) 6.0

I will repeat the experiment tonight because I am intrigued. @fantastic9888 are you still having a similar result?
EDIT: Added photo
 

Attachments

  • IMG_7047.jpeg
    1.9 MB · Views: 98
Last edited:
Today’s results.
Libre 6.8
GlucoNavii 7.0 (cold)
CodeFree 5.1 (warm)

I think that is pretty conclusive, having tested both kits in the warmth for 3 days each, that the warm kit tests far lower.

So, dear readers, are we now able to answer @fantastic9888 ’s question which was which reading is the real reading?
I tend to ignore the Libre because I can actually see it rising while I am taking the other readings. It then drops again within a few minutes.
 

Attachments

  • IMG_7053.jpeg
    1.4 MB · Views: 79
Wherever do you live that your bedroom gets that cold , on my heating thermostat it will not let it go below 15 degrees for h&s reasons .
 
jaywak said:
Wherever do you live that your bedroom gets that cold , on my heating thermostat it will not let it go below 15 degrees for h&s reasons .
Click to expand...
I live in Scotland, in a dormer room literally right under the roof with only ceiling board (which is low enough to touch) between me and the roof slates. No insulation back in the 1800s and no space to put in any retrospectively.

I have my heating in this room set to come on when the temp goes below 11 deg. I am in bed under a duvet, in nice warm fleecy PJs. I don’t see the point of heating the room any higher all night (nor can I afford to).

The kitchen directly below my bedroom isn’t heated at all. That stops my fridge and my chest freezer having to work so hard to keep cool, and as I get hot while cooking, it’s a waste of money and gas to heat a room I am only in for short periods of time.

If I am honest, the money I save on heating pays for my Libre.

Currently, as I lie here tucked up warm in bed typing this, the heating is on in my bathroom warming it to 20 deg for me to shower etc and in my lounge warming that room to 18 deg as I shall be in there working today.
 
6.3 FBG at 5.30am (not my idea!), but 5.0 at the more civilised time of 8am. Interesting. Dawn seems to be still out there, just earlier and lower than it used to be.

Also out there right outside my bedroom window.was an insomniac cockerel, he is living on borrowed time.
 
Hi @Ladynijo I think you may want to do a copy and paste into the thread “What was your fasting glucose” as this one is about the effect of cold temperatures on readings.
I can also recommend the Recipes forum for chicken dishes.
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn More.…