My Love/Hate Relationship with the CGMS

Today it’s hate. 

Usually it’s love. Honest.  I’ve typically had very good experiences with my Continuous Glucose Monitoring System and it’s done a lot for me in terms of giving me better control.  Historically I’ve been a bit of a chicken about going low, and the CGMS with its low-alarm has really helped with this.  I even have it set nice and high (i.e. 4.0 mmol/l / 72 mg/dl) so that I get an alarm even in those dropping-too-fast-for-the-sensor-to-keep-up kinds of situations.  Between this and the fact that I can peek at my levels as often as I want to throughout the day (or night), plus a few fun little graphs (I’m a math geek – sorry) it’s really been a big help in achieving better control.  So, before you accuse me of slamming my CGMS too hard, there it is.  Usually I love it.  Really really love it. 

Of course, from time to time the accuracy of a sensor is a bit off – sometimes due to bad calibration timing and/or just plain old wonky bloodsugars that make it go “Huh?!  I’m supposed to follow this?!”, sometimes due to lack of hydration on my part (drink your water people – it’s amazing the difference it makes!), and sometimes due to nothing I can identify – but these occasions have typically been few and far between. 

Until lately. 


Lately I get about two days of accuracy – max!  (I know the claim is that sensors only last three days anyway, but let’s face it, most regular CGMS users are pulling five or six days out of each sensor.)  And even those days are sketchy at best.  When my bloodsugar is in a good range the accuracy isn’t bad, but then if I’m going high or low, the sensor’s just not keeping up!  I’ll realize that I’m feeling awfully thirsty and sluggish, test, find out that I’m 13 mmol/l (230 mg/dl) and the CGMS is telling me, “Congrats!  Your bloodsugar is perfect right now!”  Other times I’ll get a downward arrow to show that I’m dropping when I’m actually going up!  These problems are pretty much negating the usual benefits I get from the CGMS!  Lately I just can’t trust that it’s ever right, and then what’s the point? 

 I’m thinking that my problems have something to do with this: 

Bendy Sensor

My Bendy Sensor

This is what my last few sensors have looked like when I take them out.  I really don’t understand why – or how – it ends up pointed straight down.  Clearly the introducer needle can’t do that, so what is happening after I take the needle out?  I’m inserting at a fairly shallow angle, so it shouldn’t be hitting anything on insertion.  That said, I have also been having trouble making the needle go all the way in with the inserter.  It goes ½ to ¾ of the way in and then just dangles there, waiting for me to push it the rest of the way.  Typically I can get it to go the rest of the way in, but it’s very odd that the inserter can’t fully insert it.  I always wrote it off to the fact that I’ve been a bit more *ahem* “fleshy” around the middle since having a baby, but I’ve actually lost the remainder of my baby weight recently and don’t really consider this to be a factor anymore.  I’m at a loss.  Something’s not working…. 

…and it’s costing me a lot of money!  That’s the other issue here.  I pay for these handy little do-dads out of my pocket.  My provincial pharmacare program doesn’t cover them, and my insurance doesn’t cover them.  At $50 a pop, the insertion isn’t the only thing that hurts!  When they’re not working I say to myself, “Self, why are we doing this again?  Those crappy 2 days of no sensor accuracy could have bought me a pair of shoes, or a dinner out, or a UFC pay-per-view!”  It’s terribly frustrating!  

Still, my inner optimist is winning because I’m still buying sensors (did I mention they’re $50 each?) and still using them….and still waiting for that one sensor that restores my faith in this wonderful but frustrating technology.


4 responses to this post.

  1. Posted by Bruce on April 28, 2010 at 12:33 am

    I’m pretty happy with the Dexcom Seven . There is the occasional short-lived sensor, but most easily last the full 7 days. And the correlation with fingersticks is usually almost perfect.


  2. I’ve had the bendy problems with my infusion sets a few times. If I see it with more than one out of the box I’ve called Medtronic and they send me new ones and let me return the old ones. Have you tried that? Very frustrating!!


    • I’ve never tried that, but I’ve had that problem with at least one sensor from every box I’ve gotten since my pregnancy over a year ago, so I’m inclined to think that it’s not the sensor in my case. 😦 I wish it was, but I think I have to blame either my body or my insertion method.


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