Wednesday, September 5, 2012

Breaking the Rules

I've become a loyal CGMS user. I rarely go for 12 hours without it. I've found that the few times I've cruised around without a sensor, I have some sort of surprise that takes me out of range. I believe that being able to head off a rise when I hit 130 mg/dl makes a big difference. My body is much more nimble and able to get the correction done if I'm still close to the normal range when I correct.

I've found that my CGMS data has been really accurate from 80-160 mg/dl. Like, when I cross-check it with my meter it's wicked close. I don't know if Medtronic updated their sensors, or if my personal chemistry is just jibing with the sensors better, but over the last few months I have been rather impressed, and have grown to trust those numbers on the display.

So, what I've been doing lately is breaking the rules.

You aren't supposed to base corrections on your CGMS reading. It's usually 20 minutes behind your actual BG, and could allegedly be wrong. But, lately, when I see myself hitting a predictable post-meal 130-140 mg/dl I bolus a unit on my pump. It turns it around.

I've written blog posts about the inherent inaccuracy of my CGMS and about how it would never be smart to respond with insulin to the wacky readings you sometimes get. But, I've noticed that things have changed, and I've changed my habits. One thing that makes it work for me is that the dose is small and the correction is timely. If it's post-meal and it's predictable, I'm comfortable with the scenario.

I wouldn't recommend this to anyone else. We all do things off-label that we consider safe, like re-using lancets, and pen needles. And, this is something that I've changed recently. If my BG gets really high (160+) I do the standard meter-check and correct.

But, this has given me a taste of what it might be like when CGMs are really accurate and you or the pump can use the data directly for minute-to-minute corrections, in real time. I'm down with it.

Ironic. I wrote this post a few days ago, and now my current sensor is doing those devious things that I thought were a thing of the past. It's diving and climbing randomly, meanwhile my meter tells me things are as stable and  predictable as ever. Hmmm. I guess if you want some good thing to dissolve, you just have to blog about it.


  1. Aaaahhh, and here I thought I was the only "bad diabetic" who sometimes corrects off a CGM reading without a fingerstick. I tend to do it most in the middle of the night, when I'm half asleep and too tired to grab my meter. (Dangerous, I know, but my sleepy mind just doesn't seem to understand). I sometimes do it with lows too, usually if I have a bit of the low fuzziness going on. Thanks for letting me know I'm not alone! (Although I will try to break these bad habits!!)

    1. Thanks for commenting, Karen!
      I had read about others doing it and thought it was kind of reckless, but when I see pretty tight accuracy I'm starting to think I can trust it.

      Call them bad habits, but who's going to be ready when the CGMs are error-free! We are. ;)

  2. I usually correct off Dexcom readings, and I corrected off on Minimed readings too. I rarely have gone wrong doing that. With minimed I ran into trouble treating false lows, mostly- because a failing minimed sensor gives false lows, and no so much false high. Dexcom sensors as they fail mostly just don't give me data at all.

  3. There were two CDEs at the FFL conference in 2011 (husband and wife -- I don't remember their names) -- who trusted their CGMS so much that they can go out without meters!