Dexcom G6 and G7 not lasting full 10 days?

It’s good to hear that you’ had success with the G6. I do too but only after the first 6 to 12 hours. After that they work fairly reliably.

As far as the grease on the G6 sensor frame there’s a grease but it’s not not intended to cover the contacts. That would be counter productive. Dielectric grease, silicone, is not conductive; that’s a common misconception. Dielectric grease used to prevent arcing between high voltage contacts and to resist scondensation and salty sweat on the sensor frame from providing a low resistance path that would short out the very weak electrical charge of the sensor wire.

When I need to clean moisture off the sensor contacts I blot them with tissue.

When the sensors don’t last the full amount of time, i fill out the online form or make a phone call to get a replacement. I do the same thing if they fall off. That accomplishes two things: 1) I get replacement sensors so i don’t have to lose days of coverage. I rely on the data. 2) If a bad sensor is reported, and Dexcom replaces enough of them, they will do a better job of finding out why sensors fail for some of us. I had far more trouble with the G6s than i’ve had with the G7. But i have had to report a few.

Hello all, I found this thread after a google search. My son, 23, is both autistic and T1D. We’ve been using the g6 for about 8 months and our endocrinologist wants us using the g6 because its the only one that talks with the omnipod system that automates much of the process.

The problem is that we have always had like a 98% sensor failure rate by day 6 or 7. We start getting the 3 hour sensor problems on day 5, and by day 6 they’re so frequent and the numbers so far off from pinprick numbers that we give up. So far Ive never had a problem getting replacements, but dexcom has finally said we’ve reached a replacement limit.

Adhesion is never the issue: we’ve never had a sensor fall off, they just start dying.

My son, despite his disabilities, is very athletic and runs several miles a day.

So here is my question:

I notice some posters seem to say that they can remove the g6 transmitter, clean the contacts, and resume to get more days’ usage. Am I misreading? I don’t see how thats possible if the g6 system requires the sensor to be “snapped” open to get the transmitter out. If it’s possible to remove the tramsmitter for cleaning without removing the sensor, I would certainly give that a try.

There are several videos on YouTube that detail how to remove the transmitter without snapping the sensor. But how I do it is I use a guitar pick (other options are a thin plastic card or a hair barrette) and slide the pick between the transmitter and the clips on the sensor. There is one clip on each side of the sensor. The transmitter should pop out without damaging the sensor. Clean the sensor and pop it back in. Don’t stop the sensor or anything and it will start picking readings back up.

You can try it a few times on a used sensor that isn’t attached to his skin to understand the mechanics of the process better. This may not resolve the issue but it is a god thing to try. If you can’t find a solution to your accuracy issues then I would ask my Dr. to write my prescription for every 5 or 7 days, whichever your more comfortable with and get it pushed through insurance.

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Here is prior post with details for G6 dexcom restart.

Originally it was quite easy, but can still be done.

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I have heard that it is more cost efficient for Dexcom to replace bad sensors (not everyone reports them) than to work on making the sensors more reliable. They get a lot of data from us about what goes wrong from actual users, but it seems it is not their policy to revise the current iteration of sensors. So I was surpised to see on the box for the B7 sensors that on the LBL line there is a REV number. This changes on different boxes. My current one says REV 011. Are they actually making improvements? If is the case, we need to be vigilant in reporting our problems. BTW, it does seem to me than the sensor lead is shorter on the G7 than the G6. I am not sure if it is related, but one pairing failed for me because the sensor lead bent rather than pierce my skin.

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Thank you! I’ll give it a try.

Unfortunately I’ve already tried the insurance route. They’re adamant that since dexcom claims 3 sensors is a month’s supply, they won’t cover more regardless of what my doctor says. And while my son has medicare as a secondary, they won’t come in unless the primary has “denied” something, and again, as long as my primary covers 3/month, they don’t consider that anything has been denied.

@EthanO I restart my G6 sensors all the time. If you have a sensor go wacky, restarting might or might not work. Since I restart mine and commonly get over 20 days, when one goes I am usually replacing it. But the good news is that I just had a brand new sensor fail on day 2 and since it was new I decided to see if restarting it would work. It worked beautifully the second time around and I am on a second restart.

No one seems to know why one person can get 10 days plus and another struggles to get to even 10 days. Lots of theories, but no one has figured it out yet.

Note to add, a transmitter near it’s expiration date can be a cause of losing communication with the sensor.

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Since you mentioned that your son runs a lot I have a few suggestions.

  1. Make sure he’s really well hydrated. These sensors measure interstitial fluid and if you are just a little dehydrated they can really start throwing bad numbers. High BG will also make them less accurate.

  2. Large swings in BG will wear out the reagent on the filament sometimes. Tight BG control can extend sensor life.

  3. Even though the sensor is not falling off, the filament may be wiggling it’s way out of his skin a little bit causing bad readings. Do you use Skin-Tac or another adhesion aid?


Hi @EthanO I suggested to Luis, who posted a very informative image of his dexcom graph, that he try cleaning the transmitter contacts with an alcohol wipe before putting it in a new sensor. The discussion we had made me re-read a few versions of the G6 manual and turns out I’ve just been cleaning my transmitter for fun. Do not try to clean the contacts on the sensor.

Please check out Luis’s image, its in the second post in this topic, and try to post something similar. This topic has many people describing different problems that all result in a sensor not lasting 10 days. You gave us lots of good info, a picture will fill in the rest.

Have you had the “Sensor Error” message persist for 3 hours then seen a screen that says “Sensor Failed”? For the most recent sensor that Dexcom wouldn’t replace what was the CGM number and what was the fingerstick (BGM) number? If you compared the the CGM to a BGM multiple times, what were those values and how much time passes between comparisons?

You said the sensor doesn’t come off, along with what Firena was asking, does it come loose in the middle? I’ve had some do that and the graph gets crazy when the sensor filament is changing depths.

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We use mastisol and have never had any adhesion problems when using it. Of course we tryto very careful to keep it well away from the filament.

Yes, that’s exactly what happens. We start getting the 3 hour sensor gaps about day 4 or 5, and then when it comes back the numbers are hugely off from the fingersticks, like 50-80 points off. (As soon as the sensor comes back online, we do a stick to calibrate) After a calibration attempt, the numbers get more in line, but then another 3 hour sensor error hits. By day 6, error frequency is such that the sensor is useless and we stop it to put in a fresh one. We actually rarely get the sensor fail message: it’s that the 3 hour temporary failures become so frequent we have to give up.

Happens to me with the G7 quite regularly. Using the non underlined LDL version (as I don’t pump). Got hold of a batch of sensor with with underlined LDL. No more problems. Dexcom DOES NOT acknowledge that this version is improved, only that it is tandem compatible. But I think otherwise. It doesn’t have the issues I had been experiencing. Do you think maybe they fixed the bugs and aren’t telling us? Please chime in!

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Thanks Ethan. Glad Dexcom isn’t (yet) denying replacements for “Sensor Failed” errors. Without the graph I’d suggest trying a different location. Here’s the site image from the G6 manual.
Dexcom G6 18 and older site selection

Here’s what works for me
Chris's sites
Red is unreliable. Blue is where I haven’t tried yet in 3 years of using the G6. Green is where the filament has been and worked great. Note I switch to my arms for the 6 months of summer. As far as I can tell the G6 should work where there is a layer of fat under the skin that has good, but not too good, circulation. Since your son also has an Omnipod you also have to consider communication, bluetooth can’t go though bodies of water, and avoid inserting the G6 filament where the last pod was injecting insulin.

When you contact Dexcom for a replacement remove any doubt that the sensor is bad. Since they have already blacklisted you I’d contact Dexcom support the next time you want to replace a sensor and get the rep to instruct you to replace the sensor before removing it. For too many sensor errors you’ll probably need to demonstrate a total of 24 hours of missing data.

A greater than 20% difference between CGM and BGM, even a 80mg/dL difference doesn’t mean the sensor is bad. When the G6 was studied for FDA review out of 9,433 samples that the CGM reported were between 70-180, 66 were off by more than 40%. I’ll abuse statistics and apply that to the 2880 readings in a sensor session :thinking: 20 readings from every sensor can be more than 40% off.

I don’t know how long a sensor has to be more than 20% off before Dexcom would declare the sensor is defective and authorize a replacement for you. If moving the sensor doesn’t work next time you have a sensor problem please Dexcom before removing the sensor and let us know what they say.

  • G6 manual
    • Page 73 Choose Sensor Site
    • Page 310 Number of Readings Provided
    • Page 284 Accuracy
    • Page 294 Table 3-C (my personal favorite) Concurrence of G6 CGM Readings and YSI Values by YSI Glucose Range (Adults, n=159)

Has anyone noticed a difference between the underlined and non underlined versions?

I lost count but I’d say that since January, I’ve had to replace at least 90% or higher of the G7s for readings that go wonky starting at day 6-8 or so with the 1 hour sometimes but usually the 3 hour warning. When numbers do come back, they are totally unreliable, give 1-5 readings, then error again. I can’t use LOOP reliably if the Dexcom G7 isn’t feeding it reliable data!

I’ve always rotated spots on my stomach because they continually fall off my arms and I don’t like it there anyway, Never tried my back and I don’t like the sound of that. I just don’t know.

This last sensor replacement request had to go through a supervisor who took several days to approve it, but it did get approved. I’m fortunate that they have been replacing them via the form. I don’t have the patience to sit on the phone and have scripts read to me. I understand the need for that, but if they have questions, they can email me and I can respond when I have time.

I just wish Dexcom would acknowledge that they have a problem and steps they are doing to fix it? It seems like they are just throwing replacements at it but the issue never really gets addressed.

I requested they replace all my (and it’s been many) non underlined sensors for all the error message addressed above, when it happens, and they refuse, even when I documented that the errors don’t occur with the underlined version. It is very frustrating, like we don’t have enough real issues to deal with. But no, I guess we can’t expect them to be user centric.