I haven't worn my sensor longer than the recommended seven days, but recently realized that many Dexcom users do. How long do you wear your sensor? If longer than a week, have you noticed any change in the accuracy of blood-sugar readings beyond seven days, or had any problems with your injection site (redness, swelling, etc) after removal? Thanks.

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I've worn mine up to 15 days. I usually don't change it until the adhesive wears away, which varies depending on the location I choose to place it. (My sensors last longer on abdominal sites but I still use the back of my arm frequently simply to change it up.) Sometimes the site starts to feel a little itchy but when I do remove the sensors, I have never seen any residual skin problems or scaring. Also, when I restart a sensor, I've noticed that unlike the first time I begin a sensor my numbers are spot on immediately following the 2 start up BGs.
I typically get close to two weeks from my sensors, and I find that the best accuracy comes at the beginning of week 2. Usually at the end of week 2, I start getting crazy readings, and that's my cue to start a new sensor. I've had no problems with itching, etc, at the sensor site. I use skin prep wipes before applying the sensor, and then put flexifix tape around the edges of the sensor adhesive pad. When I remove the sensor at the end of 2 weeks, there's never any redness or irritation, which I think is due to the protective effect of the skin prep.

Good luck!
I've typically gone 10 days w/out having to change, then the itching just gets too much!
Hi Dan, you'll find a lot of opinions/comments in this recent Thread:

"search" is your friend: upper right corner of any Tudiabetes web page. :)) Now, as I said there: I can't get more than two days without causing serious skin irritation, unless I use "skin-prep" as a barrier between Dexcom fabric and skin sweat. With it, and also using Opsite "FlexFix" tape to protect the Dexcom pad edges, I get about 16 days of lifespan -- but I replace them at the end of day 14, so that I can be certain that "needs replacement now!" doesn't occur at an inconvenient time. (Middle of the night, out at a concert, etc.)
I have worn a sensor up to about 14 days without any problems. Since Dexcom got the bad press about off-label use, I have not restarted a sensor. I have good insurance coverage so I don't have to consider cost in deciding to not extend past 7 days.
I wear a sensor until I am no longer getting good numbers. I think the longest I have kept one in is 24 days. I think I get the best numbers week 2 and into week 3.

I dont have insurance covering this so I stretch it out as far as possible.

As far as site reactions I've had none.

After a couple of weeks I start using paper tape to hold down the adhesive backing. You can get stuff like that at your local drugstore or on Amazon.
I usually switch after 7 days, unless a sensor is working really well and I want it to continue for another couple of days. I work out in the gym on Mondays, Wednesdays and Fridays, and weekends are very unpredictable, so I always want to change a sensor either on Tuesday or Thursday mornings. Those are "low activity" mornings that work great for activating a new sensor. So if I decide to keep a sensor going beyond Tuesday morning, I will kill it on Thursday. Harder though to extend a scheduled Thursday expiration to Tuesday...that requires a really good sensor and no scheduled water activities on the weekend that will make the adhesive go bad.
I've worn a sensor into the third week but now regularly change sensors at the 14 day mark. Going into the third week exposed me to needing a sensor change at an inconvenient time. I don't like being without the information that the Dex provides.

Using my sensor in the second week is not an economic decision for me. I get more dependable readings in week two. Plus it's more convenient avoiding a sensor change at seven days.

I have had a few sensors fail in the fist week but I can't remember any that failed in week two. In any case, as soon as I decide that a sensor is unreliable, I swap it out -- without regard to its installed time.
Two weeks is the charm for me. I agree that the accuracy is best during the second week. I had scar tissue in the past from injections, before using a pump, but not with the Dexcom. A friend told me that scar tissue can develop if something, like insulin, is being entering the body. With a CGM there is nothing entering the body, so there is no scarring. Only one person has told me that, but it makes sense to me.
I have scarring from when I wore the Guardian. You can scarring from a cut or any injury to the skin.
The risk of infection is lower, which probably helps prevent scarring, but definitely it is possible to scar from a CGMS.
(In reply to both Jonah and Richard157:)
Richard might have been talking about SubC scar tissue, rather than skin-surface scars. (Of course, I'm not sure.) Significant cuts will, of course, provoke fill-in by scar tissue at both levels of depth. Down at the subcutaneous level, though, Richard's exactly right about Sensors vs. Infusion sets. With infusion sets, a lot of the immunological response is created by the injection of the insulin suspension fluid.

That injection of "foreign" chemicals greatly emphasize the presence of intrusive stainless steel or teflon tubing, increasing irritation and immunological response ("IR"). None of the CGMS Sensors (Navigator, Minimed, or Dex) inject anything, but Dexcom might have a small advantage anyway: In Dexcom's Sensors, the chemicals in the core are contained by a titanium outer shell. (It's pierced with tiny hols to let ISF flow in and out of the Sensor.) This surface material might be less prone to provoking IR than Mimimed's. Or maybe not; I know of MM user who get an entire month from each Sensor, with no IR problems. YMMV, obviously. And irritation from wire movement is a big factor too: Sensor lifespan and inflammation change a lot if the wire rubs against surrounding tissue under your skin.

But Jonah, if you're talking about the skin surface, then it's more likely a difference in the adhesive. If I put a Dex Sensor directly on my skin, with nothing underneath, it creates an itchy, bright-red scar in less than 2 days- and the scar stays visible for months. (Several months ago, I had to do that during an out-of-town trip. I forgot my skin-prep. GRRRR! I ripped that Sensor out as soon as I got home.)
I usually wear my sensor for 14 days and it is an economic decision for me as I have no insurance.




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