I’ve been using a Dexcom CGM since the SevenGo. After that I had a G4, then a G4 with Share which eventually got working with an Android Wear smartwatch (Huawei 1) and Xdrip/Xdrip+. I’ve been very happy with my setup, but the chance for more accurate readings, longer sensor life, a smaller sensor+transmitter, and not needing to carry the receiver around made me want to upgrade. It just so happened that I was running out of sensors, my last transmitter was going to die soon, and my receiver was probably 5+ years old when the G6 came out so I made the switch. I figured I’d keep a log of my first sensor session to relay my impressions and experiences with it. It’s a bit long, but I hope it helps.
Sensor insertion:
I was very happy with the new inserter. The old one was fine, but every now and then it hurt a little as I twisted at the waist a bit to depress the plunger then pull up the ring. The new one doesn’t give it time to hurt- one button press and the needle pops in then retracts instantly. Very cool. I took it apart to see how it works and a picture is below. I know people are complaining about the size of the inserter, and it is a beast, but the plastic is pretty thin-walled while the old one was much thicker. Weight-wise, I don’t think it uses much more plastic than the old inserter (81g or 2.9oz). Does anyone have an old inserter to weigh for comparison? If you really want to recycle, you could pop it open like I did (snip or drill out the four white plastic nubbins on the underside & separate white & grey halves) then remove the needle assembly & other metal parts and throw it in your recycling. It’s not marked for recycling/plastic type, but I’m pretty sure it’s ABS which is very recyclable.
Sensor/transmitter size/profile:
While the G6 transmitter itself is thicker, the new shape allows the combined sensor+transmitter to be much lower profile (~9.1 mm vs. 10.8mm). It definitely doesn’t catch on stuff as much as the G4 used to. But it is just enough bigger in length and width that my old pre-cut adhesive patches don’t fit without widening and lengthening one end of the hole a bit. Sorry I don’t have a pic of the transmitter in the sensor, but I’m still wearing my first one.
Startup:
Did not go smoothly for me. I connected it to my phone running the Dexcom app first and I doubt I’ll even bother with the big annoying touchscreen receiver (aside from using it to restart the sensor). What do people have against buttons now? I can press buttons by feel in my pocket, which is impossible with a touchscreen. The old receiver was way better.
Everything went fine until I got to the part where you pair the phone with the transmitter. The menus and graphics on Dexcom app were very laggy and slow on my fairly new phone (LG G6). When I got the warning that “Pairing may take up to 30 minutes” I got a bit worried, since Bluetooth pairings usually take about 3 seconds on my phone. Sure enough, I kept getting “can’t find your transmitter warnings” and 30 minutes later I was worried. I deleted Xdrip+ in case that was causing a conflict and restarted my phone. Upon opening the Dexcom app again it still couldn’t find my transmitter. Crap. While messing with the settings suddenly my transmitter was found, connected, and working. Great! Now my 2-hour startup delay can begin- over 30 minutes AFTER I inserted the damn sensor. Grrr.
Dexcom Phone App:
Fine, but a bit simplistic and very limited. There are a selection of sounds for the alerts, but only the ones Dexcom gives you. You can’t use system sounds like Xdrip can. Also, dismissing alerts from your phone or watch is not enough- they will keep going off until you go into the app to dismiss the dialog box there, which is an additional extra step that becomes more and more annoying the longer you deal with it.
Dexcom Watch App:
I’ve been so spoiled by Xdrip+. So much information so well presented- day, time, steps, autoscaling y-axis- everything was great. In contrast, all you get from the Dexcom app (aside from their logo) is the time, a BG number with an arrow, and that reading plotted on a constant 0-to-300 scale (only alternative is a 0-400 scale!) that is too wide to easily see small changes in the range I’m typically in (70-220 or so).
Xdrip+:
I installed and started the latest nightly release of Xdrip+ up after I had the Dexcom app running so I can hopefully go back to the better alerts and watch face. Running both apps may account for some or all of the Dexcom instability issues and the problems described below.
It didn’t work at all for a day or two (error was “G5 state isn’t currently known. Next connection will update this.”), But when I looked on the second screen of the system status panel I saw that it has been connected and then see it connect then rapidly disconnect in less than a second. I sent a bug report to the Xdrip+ developers and let it go for now, but I’ll troubleshoot this more in the second week of this sensor.
Then one night at 11PM Xdrip+ give me one, and only one reading from the G6, then it stopped again. Then around 3:45AM it started working consistently until 8:30AM when it completely stopped again. Strange. but for a while I definitely had both the Dexcom and Xdrip+ apps displaying data from the same transmitter (although the numbers were a bit off). From then on Xdrip+ was connecting and downloading at least 3 hours of data every so often (eg. 1-4AM, 6-9AM, 9:20AM-12:20PM, 3:30-9AM) but this was highly variable by day and never seemed to be working when I checked. So it was probably downloading the data buffer and backfilling the readings like the Dexcom app does when the connection to it is restored.
Connection Stability:
My G4 transmitter was always tenaciously connected to the receiver and Xdrip+ was very reliable. Disconnects and missing data were rare and if they did occur it was late in the 2nd week of use and they generally fixed themselves (reconnected with no intervention). In contrast, the G6 lost connection as many as four times a day (mean of ~2x/day), requiring my phone to be restarted almost every time (toggling Bluetooth on & off only restored the connection twice). These signal losses are not because I’m far from my phone- they usually occur when I am within 5’ of it. However, when the connection is restored the data for the missing period reappears (this is different from how my G4 share worked). Note that my phone is an LG G6, which is on the approved phone list, but only for Android 7.0.0 and it has been upgraded to 8.0.
Accuracy:
I kept testing and calibrating ~3x/day at mealtimes. When the G6 was not as close to the meter reading, it was generally headed in the right direction so that it was dead on in 15 minutes, which is roughly the expected lag. It was also generally closer to the test strips than consecutive test strips (when needed) were to each other (e.g. G6 read 101 when meter/strips read 61, then 118, then 110. I calibrated to 110). I’ve also frequently seen discontinuities in the G4 plot when the calibration is off, but I never saw this with the G6 (however, this could be due to “rewriting history” as described in the Restarting section below).
Sensor Adhesion:
The G6 adhesive pad definitely does not work as well as the one on the G4, perhaps due to the slightly larger footprint of the G6 lifting it more, perhaps because it is a different shape, or maybe it’s something else. The adhesive patches appear to be about the same area, but the G4 one is football shaped (both slightly wider and longer) while the G6 sensor has straight sides and half-circle ends. The top edge of my G6 adhesive pad started to lift on day 7 and the next day I needed to stick it back down with spirit gum and a Simpatch over to hold it down (I had to cut the G4 hole in the Simpatch bigger so it would fit). My G4 sensors typically loose adhesion this badly by the middle of the second week (day 10 or 11) if at all. I only need to use the Simpatch on them every so often (in 14+ typical days of use) when I’m being really active, getting really dirty, or both. A 10-day sensor life is great in theory, but if it can’t remain stuck on for 10 days this is useless. Definitely invest in adhesion enhancement/replacement techniques if you use the G6.
Restarting:
I set an alarm to restart my sensor as per option 1 of 4 as per this site: http://seemycgm.com/2018/06/11/restarting-g6-sensors-and-transmitter/
I used my microwave as the Faraday cage (wrapping it in aluminum foil and leaving the house for a while for good measure), but when I pulled it out three hours after I put it in I first had a “no signal” error, then in a few more minutes it said that my 2-hour sensor warm-up was starting. Not exactly as the link described, but a few minutes after that warning the receiver said it was done and I hit next. But I still had the sensor working on my phone and watch while the receiver was “cooking” to reset the sensor, so no 2 hours+ of missing readings like with the G4. No recalibrations were required, but the reading jumped from a steady (for several hours) 120 up to 160. So I think it might need some calibration even if it’s not asking for it. The funny thing about this immediate jump from 120 to 160 is that after the next reading or two it smoothed the curve (the part that has already been plotted) into a steady increase. The first time I looked the 160 dot was next to the 120 dot, then next time I looked there were three dots linearly increasing from 120 to 160 with only the last one at 160 now. So it seems to move points that had already been plotted to make the curve look better. A little sketchy and this might explain the lack of discontinuities in the plots- they get scrubbed out. But when I checked before dinner with a fingerstick the 160 was more accurate.
Summary:
G6 seems to be noticeably more accurate than my G4. I feel I can trust treatments to the G6 and will try to drop back to morning-only calibrations with the next sensor. Maybe eventually I’ll trust it enough to go fingerstick free, in the first 10 days at least.
The inserter is better, although bulkier, and the sensor/transmitter is noticeably lower profile and more comfortable (catches less frequently) but the adhesive does not work as well.
Contrary to what many people were afraid of, not only can you restart the G6 with no problem (although it is more involved and requires planning), but it’s better than restarting the sensors of prior models because there’s no 2-hour downtime.
I love not needing to carry a receiver in addition to my phone, but if I had to carry the one included with the G6 I would be HATING it. It’s so much worse than the old one in so many ways.
Between the instability of the Dexcom app (I’ve never needed to restart my phone so much!) and the general crappiness of their software I’m really going to push towards getting Xdrip+ working consistently. If anyone has got a G6 working with it please let me know what settings/steps/dark magic rituals you had to do to get there. I hope all this helps someone and please let me know if you have any questions.
