Repeated Dexcom G6 failures


Yes, a physical change like this would definitely require a trip to the FDA, maybe not a new trial but it would need to be submitted. More likely is they made a manufacturing change that decreased their manufacturing costs and still allowed the sensors to perform for their warrantied time frame. It may have just had the side effect of the sensors not lasting 21+ days as they used to for us.

I base my supposition on a sudden change last year in the performance of the G5 that continued through multiple batch numbers and included observations from a number of people that I trust.


No. It’s not a total. Every time you have a failure, call them and they will replace it free of charge. You may have to wait on hold for a while, but just turn on speaker phone and wait for someone to answer.

Adding to my post from September 2018.  My son went through another 6 or so sensors in the following few months with no sensor lasting more than 2 days.  Dexcom consistently replaced each sensor but the frustration with the high failure rate eventually discouraged him from wanting to take advantage of the G6 with his Tandem connection.  I contacted Tandem to see if they had any suggestions (they didn't) though they advised G6 signal failure was generating the highest customer service call volume for them. 
While we didn't want to lose the benefit of having the G6 integration with Tandem's insulin stop algorithm, we switched to the Freestyle Libre 14 day sensor for now until Dexcom/Tandem can address the high volume  of sensor failures with the G6.  Both sessions with the Freestyle Libre lasted the full 14 days, adhesion was excellent, insertion painless and BG readings are very accurate.   Very satisfied with making the switch though we will try the G6 again once Tandem makes their next algorithm update.

The G6 system has been wildly unreliable for me. Yesterday one of my sensors failed prematurely and the sensor I replaced it with failed about 30 minutes into the warm up.
So did the other 5 sensors, one right after the other, all failed. Never had this problem with the G5. This is not the first time I have had multiple sensor failures despite following the directions to the letter, waiting 10-15 minutes before starting the sensors and moving the sensor to different locations on my person. At the end of December I had 4 sensors in a row fail. I have lost all faith in this G6 system. I am going to ask my endo about going back to the G5 system.

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Some people have no problems at all and other people seem to have repeated problems. This is why we’ve decided to stick with the G5. No need fixing (or breaking) something that isn’t broken.

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I finally spoke to tech support at Dexcom about this and I got an interesting tip from this person. He said unlike the G4, the G6 transmitter needs to be snapped in firmly narrow end first. If this is not done properly, communication will not be established and it will timeout after approximately 30 minutes. I thought I was already doing this but since I started paying close attention to this each time I insert a new sensor, I’ve not had a single problem with the G6.


One of my sensors had a premature failure so I replaced it with a new sensor. I have now gone through a total of 9 sensor failures in a row so have been without my G6 for almost a week. Dexcom replaced some of the sensors but they failed as well. I have two sensors left but am leery of using them since they will probably fail as well. Dexcom’s answer is to send me a new transmitter to see if that is the cause even though my current transmitter has full voltage and has been in use for only 6 weeks. I have reviewed at length with Dexcom possible causes for these failures but nothing I am or am not doing is an issue that would cause sensor failure. When I get the overnighted transmitter in about a week (sarcasm intended) I will try again. If that doesn’t solve the problem I will have to talk to my endo about going back to the G5. And yes, this has been incredibly frustrating because I can’t see that Dexcom has any answers to the sensor failure problem with me or anyone else.

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Hi - we are new to T1D, “G” , my 12 year old son was diagnosed 6 weeks ago and we are on day 7 on the G6. Our connectivity is getting worse every day and he constantly has to turn his phone or bluetooth on/off to get a reading. I did a fingerstick when it was first inserted as I needed to know it was accurate and it was off by 2 points - which I considered a success. 7 days in now and I felt he was running unusually high and I did another fingerstick which confirmed we had a 20 point discrepancy. Ive put a call into Customer Support and I’m still waiting for a call back. Is this sensor considered a bust at this point? The info says no calibrations needed but this seems like a big gap. Thoughts?

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Hi @GsMom. Welcome to the forum :slight_smile:

I’ve been using the G6 since December, and I used the G5 for a couple years before that.

When looking for a discrepancy, was there any reason his bg level should’ve been rising or falling? In general, I expect the G6 to be about 15 minutes behind because it’s measuring changes in interstitial fluid - not the actual bg value. There’s a lag. If you’re checking for a discrepancy, it’s best to wait until he’s been relatively flat on the G6 app for awhile and there’s no reason to expect his bg level should be rising or falling.

Did you test his bg level twice? Not all meters are created equal, and even the best meters can be off by as much as 10%. If I notice a discrepancy between my meter and G6, I always test twice before calibrating the G6.

Also, I believe the G6 is more prone to discrepancies the further out of range a bg value is. I only calibrate and check for discrepancies when I’m in range and flat.

Generally, I would not consider a 20 point discrepancy 7 days in to be THAT far off. I would calibrate it, and then test again 5-6 hours later to see where it’s running. I prefer that my sensor value be within 10 mg/dl, but I’ll settle for 15 mg/dl. There are plenty of small discrepancies that occur even when testing on my meter twice within seconds. At some point, I just have to accept that our measurement tools aren’t perfect and just work with what I have as best I can.

As for the bluetooth problems. Does he have any other devices connected via bluetooth? Those connectivity problems sound very frustrating. Hopefully Dexcom will have some suggestions on how to resolve those.

Also, my sincere apologies for the diagnosis. It sounds like you’ve already learned so much! This forum has been tremendously helpful for me, and I hope it’s helpful to you too. :slight_smile: There are a lot of great parents on here going through similar experiences.


Are you using xdrip+, or the Dexcom app? If using the Dexcom app, you should check with customer service since they should be able to help. Unfortunately if it is an issue with the phone you are using, the recommendation may be to use the receiver or buy a new phone.

I agree, and find it very strange when people post their results while exercising and seem to draw large conclusions about where their BG is headed from very small changes in BG test meter results. When I started using the Contour Next (which is apparently the highest rated of the meters) I did three tests immediately in a row, rinse and wipe before each one, and got results of 117, 139, and 128. From 117 to 139 is a 22 point difference, yet my actual BG would have been the same for all three tests. That realization made me more tolerant of CGM differences.


Well I received the new transmitter today and am in the warmup period. I have about 10 minutes for the warmup to end so far the warmup is normal so it looks like replacing my 6 week old transmitter with a new one has solved the problem of sensor failures. I wonder if Dexcom has a way to verify the transmitter is working properly.That would sure save us the hassle of sensor failures related to the transmitter. To make sure I followed the sensor/transmitter installation properly I called Dexcom to have them walk me through the process until the warmup started. Just got a beep that tells me the warmup has completed and I am getting numbers, finally! So it appears that the transmitter was not communicating with the sensor that caused all the sensor failures.

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Thank you for your response and all your helpful tips. I spoke with the folks at Dexcom today for over 35 minutes. They were able to tell that my son was closing the app and causing it to appear disconnected. That’s a quick fix. They too were underwhelmed by my 20 point discrepancy. She said to expect up to a 30% discrepancy. This seems really high to me. We did a few calibrations and now we’re back at +/- 5. Every day we learn something new!