When does "transmitter will expire after the next insertion" actually expire?

You would think that being on the Dexcom G6 for two plus years I would know the answer to this. But I have always had some transmitters on-hand, so the “transmitter expires soon” message (or whatever it said) never registered with me.

I got this message when changing the sensor on 7/20.
The transmitter was activated on 1/11.
Do I need to put on a new transmitter on the next senor change on 7/30, or ten days later?

The reason I ask is because the pharmacy says my script won’t be refilled until 7/31.

Should I ask my endo for another script?
(There’s too many categories here).


In theory, the transmitter should only allow you to start it with a sensor if it will last for at least 10 days more. (If it does not last the 10 days, you get a free sensor replacement from Dex.)

In practice, it may not always work that way.

But I would suggest trying to start it. If it starts, great. It should last 10 days. But if not, you are out nothing because Dex will replace the sensor.

At some point, when it does not allow you to start it, then you replace it.

I have only replaced transmitters when it did not allow any more sessions. The only exception for this might be if you were planning a trip and did not want to carry an extra transmitter with you.

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Maybe I didn’t ask the question correctly. I did start the new sensor on 2/20. Does the message mean that this is the last session the transmitter will work, or the next session (7/30) will be the last?
If this is the last session, then I need to get a new prescription because the current prescription won’t be shipped until 7/31.

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I’m confused. For how many days have you been using the transmitter? Not how long have you had it, but how many days was it actively used in a G6 sensor?

My understanding is that Dexcom doesn’t promise more than 10 sessions, each lasting ten days, or 100 days of use. In my personal experience and from other comments I’ve read, this is probably more like 110 days. But in either case it seems you would be well past the approximately 3 month usage life of a Dexcom G6 transmitter.

From what you said in your first post, your prescription seems to renew every 6 months? Why? Unless the script is for two transmitters per fill, it seems wrong. If you only get 1 transmitter per refill, then refills every 3 months seems to be what you need. :confused:

Since 1/11

Regardless, you will need a new transmitter. Either this session, the next session, the one after…at some point, you know you need a new one.

So get the new transmitter right away.

In the meantime, before you hook up any new transmitter, try to start the old one again after your current session ends.

If you can get another session started, great. You got a replacement transmitter before you actually needed it.

But if it does not start, you have a new transmitter.

Either way, get a new transmitter now rather than finding yourself without one that works.

How many days is “since 1/11”? 190 days? You’ve actually used this transmitter with 19 sensors for 10 days with each sensor? If so, then you’ve already done really well with this transmitter. But I would expect it to die at any moment. In other words, I’m still confused. :confused:

For me, whenever I get that message of pending transmitter expiration, it is true to its message. I get prompted to insert a NEW transmitter on the NEXT sensor start. So this means, it will expire within 10 days IF the current transmitter lasts the full 10 days.

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Do you get 2 transmitters per order? A transmitter lasts 90-100 days, so guessing you may be using the 2nd transmitter of January order. It may also die sooner if the battery itself gets too weak, more common when purchased 2 per order. (Often dictated by your insurance if 1 or 2, as carry over to when G4/G5 transmitters lasted 6 months).
If you did get 2, possibly your first one didn’t last 90 days when you switched to 2nd one?

If your transmitter battery is strong enough, you may get up to 110 days, but Dexcom only guarantees 90.

You asked the question correctly. It means that the transmitter with expire after the next session. It’s slightly confusing, but these fence-post statements are always confusing in English.

In other words, you should use the same transmitter on 7/31 (when you insert a new sensor) and make darned sure you have a new transmitter ready for 20 days, I guess, hence; August 10.

:slight_smile: I don’t believe that.

What I think does happen is that the transmitter “lasts 90 days” from the date of insertion so long as that date is not more than 180(IRC) days since you received it (based on conversations with Dexcom).

So if you get to day 89(0 based) of the transmitter you have one more day and you insert a sensor. The transmitter will then last until day 89+10 = 99 but if you try to use it after that the Dexcom app will not allow it. (Other apps have shown that the transmitter does still work, but it is understandable that Dexcom don’t want to chance letting you try another sensor; they are already running the sensors to the limit…)

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That is basically defining the warranty period.
Some people get 2 G6 transmitters every 6 months based on the supplier or insurance rules.

I prefer to get transmitter every 90 days, and can get one quickly as a prescription item at local pharmacy.

With xDrip on Android, you can get up to 110 days on transmitter. Mine is currently on day 96. 90 days is what warranty limits, so if it fails after 90, I won’t be calling dexcom.


Using Dexcom app (or receiver) a G6 transmitter will keep going past day 90. I have done sensor starts and restarts as late as day 98, with transmitter and sensor going 10 days until day 108. Not sure if day 99/109 will also work but might try it some day.

Best way to get those extra days is figure out your dates (90/98/108) and plan ahead using restarts to get on a 10 day cycle that fits the end dates).

When I used Spike app with G5 I was able to extend transmitter life until the battery truly was dead. 150+ days was typical.


What does IRC mean after the 180… 180(IRC)??
Thank you!!

If i Remember Correctly. Sometimes “IIRC” but the original form was “IRC” because it was a TLA (Three Letter Acronym).

Used to be possible to Google these things, but then someone in Google realized that hardly anyone in the world was an aging computer programmer.

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Thank you! :slight_smile:

That was also possible with the early G6 80 and some 81s. These are the ones that can have batteries replaced and be reused for another 90+ days. Too bad dexcom had to close the hacks.

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