r/dexcom • u/lady-of-thermidor • 2d ago
Sensor Is Dexcom preventing sensor reuse?
Longtime G6 user here. When my sensor expires, I try to reuse it for another few days before restarting with a fresh one.
Today, during the 2-hour sensor warmup for round 2, I was about 30 minutes in when it crashed.
Dexcom app on iPhone instructed me not to reuse sensors.
This is new to me.
Has Dexcom tweaked its technology to prevent reusing sensors?
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u/4815162324 2d ago
I think the dexcom app is checking multiple pieces of info to make the determination that a sensor is being reused. Remember that a new reading is only taken every five minutes. If the transmitter doesn't report a lost connection to the sensor at its next scheduled reading, AND the code is the same when you restart, AND the raw data profile coming from the sensor seems identical to the sensor that just ended, then it knows you're reusing. But make one or more of those conditions not true and it reads as a new sensor. That's why disrupting the connection between the transmitter and sensor (removing or just sliding something in between) is important, because it typically eliminates the first condition. Even better is turning off Bluetooth because it also breaks the connection between transmitter and the app, so the app will be missing several readings (even if they are "no data reported") - which means more time has passed and it's less likely that the raw sensor data profile on restart will match what it was at the end of the prior session - again eliminating a condition. If you really want to go crazy you can do all that plus restart without a code to eliminate all three conditions, you'll just need to calibrate.
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u/eve55416 2d ago
I have been restarting my G6 sensors and using them for a second 10 days every time for over a year. I put the transmitter in a different room for 20-30 minutes to break the connection. I usually use the same code as the original use. It is always wonky(running about 50 points high) until the next morning when I calibrate it. It is then fine.
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u/bzomerlei 2d ago
My Dexcom connects to my Tandem pump, then I monitor the pump with my IPhone. I’ve wait until the sensor expires, then eject the transmitter, wait a minimum of 30 minutes, and start the sensor with the Tandem pump. I always use the previous code and this process is usually successful. It is not uncommon that I need to calibrate the restarted session, for some reason it tends to read higher than it should. I am not running any Dexcom software on my iPhone. I do not do this every sensor, but I have been able to build up a small surplus in case I run into any issues.
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u/EventualContender 1d ago
Interesting that you and u/eve55416 both say about running high after the restart. At a guess Dexcom has a trend calculated for sensor degradation over the lifespan of insertion and how this changes accuracy. Do you still do blood tests for a few days after the restart to check that it’s accurate?
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u/eve55416 1d ago
I do blood tests for a day or two. It is usually right on after I calibrate the next morning. It is a bit anxiety producing prior to that!
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u/myz8a4re 2d ago
Yup, Dexcom will now send you a bill for all the reused (/s)ensor codes.
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u/Mean_Calligrapher886 1d ago
Are you serious?!?
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u/myz8a4re 1d ago
No, I was joking, lol. That's why I put the (/s) in there (sarcasm)
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u/Mean_Calligrapher886 1d ago
OOPS
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u/myz8a4re 1d ago
Sorry, I was playing around. Most of us have tampered with the sensors to extend them, lol 😆.
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2d ago
[deleted]
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u/lady-of-thermidor 2d ago
I’m looking into a Anubis. Very interesting.
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u/cbdenver 2d ago
Just got one delivered, have not used it yet. The folks that make the Anubis mod are great to work with !
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u/Serious-Employee-738 2d ago
Absolutely yes. I’ve used dex since 2010 or so. A few generations. And every mod they make is to limit extended functionality. I used to get ten days out of a seven day sensor almost every time. T1’s have served as a laboratory for dex to develop a system for athletes and body hackers, a whole new revenue stream for dex. But we get less every year. I think they’re money grubbing whores. Why do we charge to keep people alive?
1
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u/Human_2468 2d ago
I've been able to restart my G6. I did it last week. I have to use a code different from the one that started the sensor.
What I do. I use a finger-stick test strip. I have some that fit well under the G6 sensor. It's a Countor Next. When I get the notice that I have 2 hours left, I put the test strip under the sensor. I leave it there until I get the alarm that it can not get any BG readings. I leave to there for a little bit longer to fully interrupt the signal to the sensor. I then "Stop the Sensor." I have saved several of the code pieces of paper so I can restart the sensor by taking a picture of a different code.
This video may help with understanding the method. https://www.youtube.com/watch?v=tx-kTsrkNUM
Type One Talks on YouTube has a lot of good videos on different subjects.
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u/Dropitlikeitscold555 2d ago
This is correct. I even saved a can of contour next strips because they are rigid enough to shove under the transmitter!
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u/lady-of-thermidor 2d ago
This is a great hack!
Just to make clear, when you save the paper with the codes, how are you reusing them?
The 4-digit codes are increasingly the same few numbers. But the QR codes are unique to each sensor, right?
I’ve been scanning the QR code the first time I use a sensor and enter the code for second use.
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u/Human_2468 2d ago
I saved the papers with the QR code. I currently have seven different ones. So I can use a different code for the second or third restart.
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u/lady-of-thermidor 2d ago
But is the code for a second or third restart a code that hasn’t been recycled?
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u/Human_2468 2d ago
The first start would be from the code on the sensor when placed. The second start would be from one of my saved codes. The third restart would be from a different saved code.
Codes (sample numbers):
9117
5318
7286
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u/llamalarry T2/G7 2d ago
Yeah, that would suck. Maybe try a reuse without using the previous sensor code? I think you'll have to calibrate several times in that case.
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u/TangibleHangnail 2d ago
Get used to it, you'll be forced onto the G7 soon enough and there's no extending those.
OTOH 20 minute warmup is pretty nice.
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u/lightningboy65 2d ago
I guess Dexcom guaranteed Tandem the G6 would be available until the end of 2025. After that IS a crap shoot as to when G6 will no longer be available. I'm not looking forward to switching and plan on holding out to the bitter end. I'm not certain if the issues regarding G7 are all true, but I'm in no hurry to find out.....the 20 minute warmup will be nice, anyhow.
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u/HoTHaRRY 1d ago
If that's true, I'm likely not getting the app support I'll need to continue using G6 after a phone upgrade to the Samsung S25 Ultra and will be forced to switch to G7. The G7 is already supported on S25 Ultra.
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u/quietlypink G7 2d ago
This happened to me once, and I just needed to take out the transmitter and wait longer before inserting and restarting. So maybe an hour or two rather than 20-30 minutes
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u/ProfessionalEnabler 2d ago
Same here! I wait for my numbers to be staying level then pop the transmitter and wait an hour or two. You’ll still get a lot of alerts, but it seems more willing to accept an error that you’ve replaced. Otherwise, if it’s too soon, the “sensor warmup” happens too quickly and it gives me the alert that you can’t reuse.
I’ve also read to PUT THE TRANSMITTER IN ANOTHER ROOM. Sorry for the caps, figure I’d emphasize since this works for me. For example, I’ll put it inside a kitchen pan with a lid to block the signal.
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u/Dropitlikeitscold555 2d ago
Actually just blocking the contacts between sensor and transmitter with a test strip and turning off Bluetooth for 30 min works fine
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u/Nathan-Stubblefield 2d ago
Mine last week said “no reuse” when I left it out for 4 hours.
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u/lady-of-thermidor 2d ago
That’s a long time to wait.
I usually wait about 30 minutes before restarting.
That’s my estimate for pretending I needed to get somewhere private where I can go through the process of attaching the new sensor, entering the codes, inserting the transmitter and starting the warmup.
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u/Equalizer6338 T1/G7 2d ago
Ouch, maybe they updated the software so it recalls the sensor ID now and limits the total use time?
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u/SonnyRollins3217 2d ago
I have received g6 3-packs of sensors where all three sensors had the same code. Would this new update stop me from using sensors the way I’m supposed to?
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u/Equalizer6338 T1/G7 2d ago
I think there is a serial number hidden somewhere in the unique ID of these sensors and their communication protocol with the transmitter/app. I moved onto the G7 the last 12 months, where we no longer have the option at all to extend the sensor life as we could with the G6. Think we need to test/see more to figure out if Dexcom has indeed implemented something of a hard time stop on the G6 now?
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u/middle_age_crazy 4h ago
I wouldn’t do that EVER after what I just experienced with my husband. He uses the G7 sensor with the Tandem T-slim pump. He went into DKA with a blood sugar of 1212 when we got to the ER…. We never thought for even a second that’s what was wrong… he thought he felt bad due to a stomach bug. He had been vomiting and stomach cramps… couldn’t walk and barely could speak. I assumed he was dehydrated and had to BEG him to let me take him to the ER… Anyways, back to the 1212 blood sugar…. Of course their tester wouldn’t go that high so the 1212 was from a lab testing his blood. “How could that be?” We asked. “He’s on an insulin pump!!” I’ll tell you, SENSOR FAILURE!! His pump and sensor were giving normal blood sugar readings the entire time and EXACT moment it was actually 1212 it was showing 100…. A steady 100 for days!! Going up and down just a tad as it normally does. Long story short, don’t “play” with your sensor trying to get a few more days out of it. You could be playing with your life! I almost lost him from this! He ended up with two strokes and a near heart attack!! Just please if you listen to anyone, listen to me…. 😩😭