My next Dexcom Sensor will be inserted on Day 89 of my current transmitter. Can I safely use the transmitter one more time or should I start a new transmitter on that day?
I don’t want to use any special tricks or techniques to convince the Dexcom app that I’m using a new transmitter or something. I just want to know what will happen if I simply proceed as normal with an 89-day old transmitter. Will the software do anything to shut it down before day 99?
For background, I never used to worry about this because I used the Dexcom app to start all my sensors (a bad idea leading to a lot of sensors in once-a-day calibration mode) and the app would not let me start a new sensor session if it deemed the transmitter unable to last 10 days so I never thought about it. Now, I start all my sensors from my T-slim pump (a much better idea leading to “no calibration” sessions), but recently the T-slim let me start a sensor and then the app or the T-slim (not sure which) immediately cancelled the session because the transmitter was too old, thereby wasting a sensor (which Dexcom replaced, but still…) I don’t know what day I was on when that happened.
Basically, I don’t want to lose a sensor before 10 days are up by not replacing the transmitter, but I’d also rather get a little extra life out of a transmitter if someone knows that the app and/or the t-slim is not going to cancel the session after it has started.
I do not use a T:Slim pump but do use a Dexcom G6 connected to a Dexcom receiver and an iPhone with the Dexcom app. In my experience, I can insert a new sensor on transmitter day 99 and still get a 10-day sensor session. In fact, I’m on day 102 right now, 5 days into a sensor session.
Just thought I’d let you know what those of us with just the Dexcom receiver and/or app experience. I trust you’ll get some other comments from users of T:Slim and G6, perhaps @MM1 or @Robyn_H.
I cannot comment on T-Slim CGM interface, but with a Dexcom receiver not only can I start a sensor in Day 89 of the transmitter and use it all ten days, but it will also let me start a sensor on Day 99 and get all 10 days.
Yep, you’re fine. There actually aren’t any tricks anymore to extend transmitter life. There’s a hard set maximum life span of 110 days, no matter how much battery life remains. 90 days is actually the warranty period, not the lifespan. If your transmitter stops working on day 89, then you get a free replacement. If it stops working on day 91, then you replace the transmitter at your own expense. You have until day 99, 59 minutes, and 59 seconds to start a new sensor session. Once the clock flips over to day 100, it’s too late.
The t:slim pump will actually let you start a new session on day 100 or later, but will quickly fail and return an error code telling you to change the transmitter now. There’s something stupid in the communication protocols. It doesn’t tell you when the last possible session ends and before you plug it in to a new sensor. It essentially wastes a sensor every 3 months, if you’re not paying attention, and you don’t know how to remove the transmitter. (Tandem will send you a replacement though)
The same deal with your tslim. You can start on day 99. But I find the transmitter starts giving me trouble after about 80 or so. And it starts warning you that your transmitter is getting old. It’s annoying
I need to have my pump closer when I’m near the end.
Also I get 9 sensors and a transmitter every quarter so I have no reason to extend them.
My insurance just does it that way.
I had an extra sensor after my last set because I had one replaced. I started that at day 89 and ran it to 99. So technically I didn’t go over.
If you are able to start a new sensor then the transmitter will work for its normal duration. Only after the transmitter is expired it will not allow you to start another sensor session. I’ve done this many times. My understanding is this is intentionally supported by Dexcom.
Yes, at this point (day 81) I do seem to get more lost signal alerts from my iphone than I did when the transmitter was fresh, but the contact with the t-slim still seems pretty strong so it seems worth another little while…I like having an extra transmitter on hand which I do now but won’t for the rest of 2021 after I start a new transmitter.
That explains it. I must have been on day 100 when that sensor got wasted. Tried to remove it but it was on the back of my arm and I just couldn’t seem to pry it out from that angle. Agreed that it is something stupid in the protocols because it let me start and then stopped it right away.
The Dexcom transmitter has the logic built in to identify if the battery can last 10 more days when connected to a new sensor, the number of days post 99 is a timing thing, if starting on day 89 and it lets you start a new sensor, it will last the full 10 days.
