Yesterday, I had three Dexcom G7s fail in a row. I spent probably a couple hours with customer support and they’re replacing all of them.
All three failed in the same way. They never connected to either the iPhone or my Tandem pump. In a couple instances, I got the pairing request message on my iPhone, but the pairings didn’t take. Sometimes, the searching for sensor whirled around endlessly. Sometimes, the app repeatedly returned to the start sensor screen / no active sensor.
Dexcom thought I was unlucky and had three defective sensors. I can’t help but think that I messed up in some way. Three in a row! What are the chances? I’ve used G7s on and off for about 7 months and, while I did have two previous failures at different times, nothing like this: three in succession in basically the same way
Here are the troubleshooting things I tried (usually multiple times):
turned on and off Bluetooth
Turned off and rebooted phone
Uninstalled and reinstalled the Dexcom G7 app.
“Forgot” all the old Dexcom sensors on Bluetooth
Uninstalled sugarmate app from my phone. (Can’t really think how this app could affect pairing in any way, but Sugarmate was new on my phone since I’d last started a sensor.)
Anyone have anything like this happen? Any other troubleshooting tips?
I’m wracking my brain, and, it’s possible I allowed one or two of the sensors go through the baggage scanner at an airport on a weekend trip recently, but I did not bring all three for one weekend.
I’m using a G6 now and have not reordered G7, though I will be getting those replacements and hope to be able to use them. I like overlapping G6s and G7s to avoid the first 24 hours of bad readings. For the first G7 start, I did have a G6 running but that hasn’t caused problems in the past and I took off the G6 before trying to pair the last two failed G7s.
I usually don’t try to connect to a G7 until about 12 hours after it’s been inserted. This usually results in the app returning to the start sensor screen, but if I wait 5-10 minutes it always connects eventually.
I think what’s happening is that the sensor limits how often it sends “I’m here” packets to save battery power - sending them fairly often when it first starts up but drops back to once every five minutes (when it sends blood glucose values) after while.
I always ”forget” the old sensor Bluetooth device after the sensor session ends.
That tip about the magnet is interesting. One of the customer service reps told me to hold the applicator up to the sensor. It seemed odd but I dutifully did it wondering what it was supposed to do. I certainly didn’t rub it up against the sensor, just vaguely held it there. If it happens again, I’ll try holding it tight against the sensor and moving it around.
An update: I looked at the lot numbers yesterday and the three failed sensors were all from the same lot.
I inserted a new sensor from a different lot last night and started getting readings this morning as soon as I paired (These days, I usually overlap and put in new sensors the night before I start them to hopefully avoid a night of false lows and alarms.)
If I get another bad lot, I’ll definitely try the magnet trick. It makes sense that it might have been that because the sensors weren’t generating failure notices or anything. They just never paired. If the magnet thing works, it would allow you to presoak without using up any of your 10 days which is otherwise not possible with the G7.
Anyway, between the lot numbers and the new sensor working, I don’t think it was my phone or my technique. Just a bad lot.
I just got my 2nd batch of 9 G7 sensors, a 90 days supply. In the first batch, 6 failed and were replaced. So I recieved a total of 15 sensors, 6 of which failed so far. The 1st 3 were on day one. I still have 3 or 4 of the first batch to use before starting the 2nd batch. That’s a failure rate.
The most recent failure, I noticed the sensor wire was bent and poking through the hole on the top. I didn’t notice it on as of the others, which doesn’t mean it didn’t happen.
I have this happen with the 90 degree cannulas all the time, feels like it went in normally, but then my sugar soars and I look and that cannula is bent in half.
Random troubleshooting is good, however, the actual Dexcom user algorithm is the winner.
Contact your local Dexcom clinical rep for orientation. Your prescribing health care provide should do this for you.
I am a 25 year Dexcom user and have had orientation to every model prescribed. The most frequent cause of CGM failure is hubris on the prescriber or user in avoiding orientation.
I’ve used G7s successfully before and since the three failed sensors so I don’t think that’s an issue in this case.
To your point, though, I’ve never been offered any Dexcom training going back to the G4. It might have helped early on.
Do you think the orientation helped in any way with the lack of accuracy (for me and, I think, some others) in the first 24 hours? I find I just have to wait it out (without calibrating in my view) until the sensor becomes accurate (which it almost always does for me).
Just to finish the thought. I inserted a G7 last night to let it “soak” overnight and this one did not automatically start on insertion. The magnet thing DOES work, though, so I was able to start it this morning just by holding the magnet over the sensor. A win from my point of view since I got my presoak without using any of my 10 days and 12 hours. The sensor is reading well.
Unfortunately, the “failure” to automatically start (aka the feature of not starting automatically) on insertion doesn’t seem like something I have any control over. It just happens sometimes. Too bad I returned the 3 sensors from the lot that didn’t automatically start before I learned the magnet trick.
The first question about any Dexcom CGM failure is, “Did you attend the Dexcom orientation conducted by the Dexcom clinical rep, your endo was to schedule as part of the prescription process?”
Did your hubris filled endo blow of inservice with “CGMs are slap & read.”
Not sure hubris is the right word, but I’ve used 4 versions of Dexcom (G4-G7) and I don’t remember ever being offered training. Possibly I had some kind of training for G4, but I don’t think so. Also, don’t see how training would have prevented these failures. Knowing the magnet trick would have, but doubt that’s part of the official training.
I have you beat by 2 models. The two before G series.
With every model change, I was offered in-service by the nurse educator in the endo practice. It may be my professional standing as a nursing school faculty enhanced the offering. However, I can assure you every CGM user was sent to training with every model change. The education was and continues to be part of the information shared with prescribers. Send your patients to orientation.
Dexcom CGMs (every CGM for that matter) includes statements similar to insulin pumps about not to be used without proper instruction.
I stand by hubris or arrogance on the part of those believing medical devices are “fumble thru” and get the best you can and then belly ache because something doesn’t play nice.
I have been using G7 for a year and had no unexplained failures. I have completed the online replacement form after following the inclass check list to document things like dead batteries.