Dexcom G6 Transmitter Expiring Alerts

What have people’s experiences been with the “Transmitter Expiring” alert for the Dexcom G6?

I have now been on the Tandem tslim and Dexcom G6 for about a year now and for the FIRST time I received an alert saying the “Transmitter Expiring in 23 days.” In the past I have always kept my own records to keep track of 90 days from the time I first used a new transmitter. I always heard I should receive such an alert but have not until just recently. Perhaps this was due to updating the software in my Tandem.

If you have received these messages before do you find them to be accurate? Do you use a new transmitter when you are changing your sensor 10 days prior to the day the alert is reporting expiring OR will you continue using the transmitter if you are scheduled to change your sensor a few days prior to it expiring? For example, if you installing a new sensor today and you had received an alert saying your transmitter will expire 8 days from now, will you push it and wait to install a new transmitter ?

I am trying to maximum the days I use a transmitter having to pay for it out of pocket.

I look forward to hearing your experiences.


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Hi Scott @Scott, like you, I’ve always kept a record [two places, at least] when I start a new Transmitter and highlight 90 days hense on my calendar. Unlike you, I’ve always received the “23 day alert” from Dexcom, and usually shortly after that notification I get a “30 day alert” on my Tandem pump. I change out my transmitter when changing the sensor that will expire between those two dates and have not had any problem. All Transmitters HAD lasted more than 90 days.

That said, On this past Sunday, at about 11:00 PM, I got an “Out of RANGE alert” on both my phone [secondary receiver] and on my Tandem t-Slim - the phone was on the arm of my recliner about 18 inches away from the unobstructed Transmitter, and my pump was hanging on the neck of my t-shirt about 8 inches away. Needles to say, the repeated alarms didn’t let me sleep. Still no signal at 2;00 AM so I started a new sensor - on the 84th day.

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The transmitter is accurate, the reason it expires is due to limited battery life. It’ll transmit until the battery dies but the warning is a method to alert you and not waste a sensor.

Because batteries are not perfect, it is possible that the transmitter dies before the timer expires. Dex should replace a transmitter that dies “early”.

There are some skilled DIY’ers out there that grind the transmitter, replace the battery, and use it again. I think it was relatively easy on the G5 and people show how on YouTube… almost positive that it is hard/impossible with G6. anyway… just additional information. cheers

I recently had an expiring transmitter. There were warnings to make sure I had a new one in a few weeks. On the last session a notification stated that this would be the last session on this transmitter. Note, I do not use the Tslim and start my session from an iphone. That transmitter had lasted more than 90 days.
The previous transmitter had an early battery failure and quit a few hours after a low battery warning. I don’t recall the number of days but it was less than 60. The notifications were clear that something was wrong but it didn’t give any real advance notice, just a few hours.

I copied the following out of Dexcom’s online manual for the G6 - the portion in italics is mine:

13.4 End of Transmitter Battery
The transmitter battery is good for up to 3 months.
How do you know if your transmitter battery will last through your next session? If you haven’t received your final 10-day transmitter battery life warning, you can reuse the transmitter for your next session. Starting at 3 weeks before the end of its battery life, the warnings count down the transmitter battery life until it has only 10 days – one sensor session – left. If the transmitter battery has 10 days or less remaining, you won’t be able to start a new session. See Chapter 14 Troubleshooting for more information.

I have gotten a 10 day warning, followed by a reminder several days later that I had perhaps a couple of days left (it’s been a while so I don’t recall exact details) - only to have it give up the ghost a few hours later😡, with days left on my sensor!
Thankfully I get my replacements so I have my new one on hand; still it is frustrating to start a sensor and be unable to use it for the full 10 days, even though Dexcom did replace it.
BTW, does anyone besides me wish the CGM alerts listed a specific Transmitter Expiring error? As it is you have to scroll through day by day to find it. Sometimes I need a reminder of days left, and scrolling through those day by day alerts is awfully tedious.

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Dorie, expiring error, or expiring DATE?
On the Dexcom app you use on your phone, tap Settings in the upper right, then tap Transmitter, on the fourth line down, appears “Activated on followed by a date”. My app currently says 1/3/21 so I just need to count 3 and get April 3rd - of shortly thereafter.

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Thanks @Dennis. It was the date. I use Tandem’s TCONNECT app (suggested by someone who was helping me set up CIQ) but not the Dexcom app so I don’t have access to all the info. I try to remember to make a notation on my calendar when I start a new one.

I have been wondering about this as well. I have been using Dexcom almost 3 months now and just got the 30-day warning. It will have been 90 days coming up in about 10 days, so that confused me. The med supply company I use will send me a new transmitter on the same schedule as the 30-day supply of sensors and infusion sets and I know the exact date from my pump Tslim cgm history. It seems chancy to continue using the transmitter beyond those 90 days based on a message about 30 days–though I agree that message is confusing and should not be used!

This info is also available on the tandem pump. Options>history. Look for the session that includes transmitter ID. I also use the TConnect app, not a separate Dexcom app. Curious if the Dexcom app is value added. I can already follow everything on my pump and on my iPhone through Connect.

Elizabeth, it is chancy. I always order separately a new transmitter from my supplier [Byram] about two months before I expect the one in use to die.

Just two weeks ago, I got the Dexcom “23 Day” warning/alert and on the same day, I received the Tandem “30 day” Alert. Fine, on my calendar I bracketed the 23-day and 30-day “switch transmitter” period figuring that I’d start my new transmitter when I changed sensor between those dates. A few days after I received the 23-day alert, I got “signal loss” alert at 11 PM - the continued alarms kept my up out of bed, and at almost 2:30 AM. I got a "Change Sensor alarm followed by a start new transmitter message. Thankfully U had everything close by, and even in my stupefied state was able, after failing three times, enter the correct “pairing” number. Did you know that to a half-bling guy with eyes that water, that the letter “B” on the transmitter box looks much like the number “8”?

Well that sounds fun! haha I think I am going to just plan on changing the thing every 90 days! I haven’t done this yet, having just started on the tandem/dexcom combo less than 3 months ago. Gotta say, it doesn’t sound like they have this aspect of the “hybrid closed loop” well thought out yet.

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What I failed to say Elizabeth @elizabethm , it was Day 84 that my transmitter ceased working.

Have you called Dexcom about this? I wonder if they will replace that transmitter. This would be a real problem for me, as my supplier will only send out new supplies on the 3-month anniversary of the original send date. This seems crazy to me and really only works at all because I didn’t actually start using the tandem/dexcom combo until more than a week after receiving the original supplies. Still, I am on my last sensor and have had my first transmitter warning and if either died prematurely I would be without replacement. If I have a transmitter die even a few days early I will definitely be complaining about that to Dexcom! (And from what I am reading, sounds like I def will eventually)

If you have issues with your transmitter or receiver definitely call Dexcom. Although your equipment supplier is held to a schedule Dexcom will replace devices that fail or have issues in most of not all cases. I’ve gotten replacements for a bad insertion site, or because I dropped the applicator and our “discharged” before I put it in (that was a G5) and because it mysteriously stopped working for some reason (rare), and if the sensor stopped before 10 days.
I keep a Freestyle Libre on hand on case of emergency - it doesn’t do everything Dexcom did but it beats the heck out of pricking fingers!

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Dorie always seems to say this. Thanks to that I actually got a sample from my endo last month and tried it. Turns out it works pretty good for me. Really didn’t like the reader but the sensor profile and accuracy was pretty good compared to a g6 I was also wearing. No issues with the sensor at all.
SO I am going to get a FSL 2 backup and suggest you do the same.