meters temperature sensitive?

2t9nty

My BG readings have been higher now that fall has arrived. This happened last fall/winter too. I thought it was just me. Wondering if the meter was temperature sensitive, I decided to conduct an experiment.

Check fasting BG on rising - 117
Put the meter in the pocket of my sweat pants for 5 minutes and check again - 99

I am curious if anyone else has ever tried this?

amyfrogred

Wow! My numbers have been higher this week and the temperature has dropped(not much in Southern CA) but maybe enough. My meter is kept in the same place in a tray on the coffee table near a window.

2t9nty

amyfrogred wrote: »

Wow! My numbers have been higher this week and the temperature has dropped(not much in Southern CA) but maybe enough. My meter is kept in the same place in a tray on the coffee table near a window.

Is the temp in the house fairly constant? Just for the sake of science, you should try this experiment. Mine went up last fall too and stayed higher than I liked. I thought it was just the body's way of dealing with colder weather. The A1C in January was better than I was expecting from the readings. When I started getting higher ones again this fall for no good reason, I thought I might see if the temp of the meter (or mine anyway) made a difference.

amyfrogred

It's definitely colder at night, since I take my blood first thing in the morning it could be that my body is colder also.

2t9nty

That may be. I am of course curious about thus. I called and am getting the company to send me some testing solution so I can test it with the solutions at different temps.

rheddmobile

Interesting. My house meter is in a controlled temperature place (downstairs half bath) but I know my purse meter is much higher in hot temperatures. I haven't tried it with colder temps.

2t9nty

I got my testing solution - it was labeled "normal." The range on my strip bottle said 86-107. I tested at room temp (60 degrees or so) and got 100. That is in the range. I put the meter in my pocket for 10 minutes to warm it up. I am not sure of the temp here, but it would be less than body temp. I checked with the solution again and got 93.

So... both readings were in range. The warmer meter gave a lower reading.

nvmomketo

Wow. I never would have expected that.

mickj2018

My meter got left in the car the other night, when I brought it and my reading was 145 which is way higher than normal for me. Hadn't eaten anything out of the ordinary and was testing at my normal times so I would say cold does seem to affect readings.

rheddmobile

2t9nty wrote: »

I got my testing solution - it was labeled "normal." The range on my strip bottle said 86-107. I tested at room temp (60 degrees or so) and got 100. That is in the range. I put the meter in my pocket for 10 minutes to warm it up. I am not sure of the temp here, but it would be less than body temp. I checked with the solution again and got 93.

So... both readings were in range. The warmer meter gave a lower reading.

The range of normal variation is about 10% - I've tested the same blood drop twice within ten seconds with the same meter and gotten a seven point difference. Unfortunately tolerances are not precise, so while interesting, this doesn't give any information unless it's repeated many times.

2t9nty

If I were more of a scientist, I would go though a bunch of strips getting more samples. The temp sensitive thing does correspond with my experience in the past though. At some point someone else will get some control solution to remove the finger stick variable and maybe try it themselves.

rheddmobile

2t9nty wrote: »

If I were more of a scientist, I would go though a bunch of strips getting more samples. The temp sensitive thing does correspond with my experience in the past though. At some point someone else will get some control solution to remove the finger stick variable and maybe try it themselves.

I have two identical meters which have been tested against each other and read the same. I could stick one outside for a few minutes and try it at the same time as one kept inside. My control solution is old and probably has evaporated some, which means it will read high, but if I test both on the same drop it should at least be consistent to itself.

2t9nty

rheddmobile wrote: »

I have two identical meters which have been tested against each other and read the same. I could stick one outside for a few minutes and try it at the same time as one kept inside. My control solution is old and probably has evaporated some, which means it will read high, but if I test both on the same drop it should at least be consistent to itself.

I will be interested to hear results.

rheddmobile

Okay, I don't think there's any doubt. Blood glucose meters are very temperature sensitive and read higher in the cold.

I have two identical meters, Bayer Contour Next. In the past they have consistently tested within ten percent of each other. The manual for Bayer Contour Next states that it is accurate between 41 and 113 degrees Fahrenheit but should be allowed to reach the temperature of the room in which it is being used for twenty minutes before use.

For this experiment I used Meter 1 as a control at 71 degree room temperature and placed Meter 2 first in the crisper drawer for five minutes which a thermometer measured at 41 degrees, then in my bra (presumably close to 98 degrees) for ten minutes until warm to the touch, then next to the control meter for 20 minutes until room temperature to the touch to check that the two meters were still accurate to each other. For each test I used a single drop of lvl 2 control solution which is supposed to read between 110 and 137. All room temperature readings were within this range. I took two readings for the first test and a single reading thereafter.

Cold test
Meter 1 (71): 1st reading 134, 2nd reading 131
Meter 2 (41): 1st reading 167, 2nd reading 165

Warm test:
Meter 1 (71): 132
Meter 2 (98): 113

Room temperature test:
Meter 1 (71): 134
Meter 2 (71): 128

As you can see, the room temperature readings were all within ten percent of each other, while the cold readings were thirty points higher, and the warm reading was twenty points lower. I'm suspecting that if I had waited longer than twenty minutes before the final reading in order for the experimental meter to return completely to room temperature, the final reading would have been even closer.

2t9nty

More data is always a good thing. I appreciate your testing things with your meters.