I an Electrical Engineer and a 15 years user of Dexcom CGMs. I have been using the G6 up until recently and have been quite happy with it as I only had one early sensor failure in 3 years and the only issue is accuracy for the first 12 hours but soaking helped that issue.
I have waited 2 years after the G7 was introduced hoping the issues like I read data showed 25% of the sensors were failing early for a number of issues with sensors older than Rev 008 and FDA release an alert about that. My sensors are from Rev 010/011 but I’m still seeing issues with my G7 showing erratic readings and seemed slower to respond to blood glucose changes so I inserted both a G6 sensor I was saving and G7 sensor to do a comparison. What I found is that even though both follow a similar trend and steady state accuracy, the G6 graphs were so much smoother and responsive, tracking my trending blood glucose levels really well compared to the G7, which I also verified with finger sticks.
Question is are other people seeing the same thing? I am wearing the sensors on my upper buttocks, a location I really like and worked well with the G6 and am wondering if that location is part of the problem? I did read that the upper buttocks is a recommended site for the G7 in children so why not also adults?
I do like all the new features of the G7 like direct to watch and improved software, but to me accuracy and response are way more important so I am somewhat disappointed I switched.
I like to hear others experiences as I have not seen these specific issues discussed before?
" Dexcom’s FDA warning letter reveals unauthorized changes to sensors"
I understand that but I saw in my comparison that the G6 does a better job. The graphs on the G7 are not as smooth. The response is also slower than on the G6? When I do a blood glucose test on rising or falling levels the G6 follows it better. What’s your experience?
Thanks for your report, Mike. I’m still holding back on the G6 for as long as I can. Since the G6 provides minute-to-minute guidance to my pump as part of my DIY Loop, I remain skeptical of the G7 upgrade, at least for me.
Going from an angled sensor orientation to a 90 degree sensor makes me think my body may not like it. I could be wrong and hope I am. In the last five to ten years I have lost a fair amount of weight and at 71, I am an older man.
When Dexcom finally pulls the plug on the G6, I’ll be forced to make a decision that for the first time since 2009, I’ll have to consider other manufacturers.
The G6 graphs being smoother is the result of the software smoothing that @mohe0001 mentioned. This smoothing actually slows down the response of the G6 sensor, but may result in fewer false reactions to CGM noise.
When I first noticed the smoothing was when I went back through the data later to try and understand why I ate a snack at a particular time, but couldn’t. What I discovered was that the smoothing does two things: it makes the G6 sensor look less noisy, but it also changes history. If you make a note of the current blood glucose value that you see right now and then go back five minutes from now you will often find that the value that has been saved in Dexcom’s history is not the one that was initially shown to you. This is especially true if BG is changing rapidly. In particular it makes compression lows appear much smaller in Clarity than they are when the G6 first reports them.
As someone who has experienced a lot of compression lows I was hoping G7 would do better. It doesn’t, but at least it doesn’t try to hide the evidence that they happened.
