As of Monday this week, (8/29/17) I started on the 670G and as a result switched to the Guardian 3 CGM system–my biggest misgiving about the whole deal. Thing is, I already had a Dexcom G5 session going, so rather than pulling the plug on it I’ve kept it running in parallel, just to see what kind of variance there is between them. After 48 hours, I gotta say, I’m not seeing any. A lot of the time the readings are actually identical or within 10 units of each other (I’m wearing them both on my abdomen, one on the left and one on the right). The variance increases as I get further out from 100, either way, as you might expect, but still close enough that I feel surprisingly confident about the Guardian being as good as the system I’ve trusted for 3 years. Big relief, that.
Biggest differences maybe cancel each other out: The Dexcom has been a lot more prone to Bluetooth dropouts, while the Guardian3 was a much more elaborate PIA to get inserted and taped down. Those dropouts would be a lot more problematic for running the 670 in auto mode (which I won’t start until next week), so the Guardian’s reliability is significant. On the other hand, from the beginning of switching from MDI to pump therapy I have always really really really hated all the finagling little doodads and whatnots you have to fiddle with to get everything running (failure points! many!), just something that goes against my grain, and I have a feeling the sensor insertion process is going to drive me nuts, vs the Dexcom’s rather elegant simplicity. Ah well, this is what spouses are for.
Also too, and apropos of nothing: turns out I am the first patient at Brigham & Women’s to go on the 670G, so I definitely have the attention of my in-house and Medtronic trainers, both very keen to have this work out well.
Anyway, I’ll keep the dueling CGM experiment going until at least next week, when I switch on auto for the first time. I’ll try to keep y’all posted on how it goes.