Monday, September 24, 2012

Expired sensors: I'm stubborn and frugal, but...

Right after I posted about trusting my sensors enough to use them for corrections...  I went on a run of 3-4 sensors that just didn't have it. I wonder if there is something about body chemistry that throws them off. I had such good results for a long time, and the sensors were even expired... More recently I had to toss out the box I was using because they were consistently inconsistent. Yes, they were expired, but that's not always a deal breaker.

The straw that broke the camel's back... I was doing weekend work (catering) which included a lot of hustling and moving of somewhat heavy stuff. My sensor showed me going up, and showed me at 150 mg/dl. Since I've been fighting a cold and running higher BG it' didn't seem that strange to be climbing while being active. I felt more on the low side with a jittery-ness that didn't feel high at all. I tested and found that I was 44 mg/dl. By the time I tested, my sensor was reading 180 mg/dl. So, not only was it off by a lot, it was actually showing movement in the wrong direction. Times like that, you just want to turn it off because it's no help, and you are getting false alarms.

This brings me back to my theory about body chemistry. I have read that Dex sensors are made inaccurate by using acetaminophen. Could there be things in my sinus spray that enter my system and cause my interstitial fluid to less readable by the sensor?

I've also been seeing my sensor stay the same while my meter shows an upward trend for over an hour.  So, anyway, I've tossed out the box of sensors that expired in February and now I'm using a box that only expired in June. Why do I have so many expired sensors around? Because I found that I'm able to get 6-7 days on them, doubling their life. Putting them in once a week is a really good trade-off of pain and bruising to useful data. When the data is useless, you wonder...


  1. Interesting thought about the nasal spray! That's something I wouldn't have considered.

    I sleep with a CPAP machine, and there are some nights when my nose is stuffy - making it hard to use the machine. I often resort to using some sort of nasal spray to help me get the air I need. I should pay attention to whether it throws my Dex readings off.

  2. I think either some medications or some illnesses stop the sugar from moving to/from blood/interstitial fluid the way it usually does. 'Cause my experience is that Dexcom is less accurate when I'm sick. And I've heard other minimed users complain of inaccuracy when taking medications for minor ailments. And minimed claims its okay with acetominophen... but they never did collect data to back that up.