I am farely new to the Dexcom 7. I have also had some problems keeping my sensor on my body. I have now found a very comfortable spot that is sweat-free. So I have now worn my Dexcom for the longest I have ever had it on (6 days). Before that I have only worn it for 3 days the longest.
I am noticing the last day or so, that the accuracy is about 20-30 off. Once I even had it say 193 when it was 87.
Does anyone know if this is normal, when you get to the last day or so?
I have noticed that when my sensor gets to the end of its life the numbers will be way off…although, I think 20-30 is technically reasonable.
Since I am able to get more that a weeks use out of my sensors the crazy numbers are really the way I know its time for the sensor to go…although at 6 days a reading of 193 when I was 87 wouldnt make me rip it out that instant. I’d calibrate and see if it sorts itself out. Sometimes it will and youll get a couple of more days out of it.
Re only getting about 3 days - have you tried it on your leg? I find that my thighs, on the outside, are great for Dex. Not so much in the sweat department and I put down some Skin Tac (sp?) before sticking Dex down and that seems to help also.
Well, I initially started with it on my stomach. This started coming off by the end of the first day, even with skin tac. I just tried (current sensor) above my backside, about the beltline. This has been perfect for me!! did not peel up at the corners.
I’m glad it works there 
For me my legs are the only place that it is comfortable…I tried my arms and they were a no go and I tend to reserve my torso area for pump sites.
I dont know what else you can do to help with the sticking…There is the SkinTac that you are already using and you could always put a Tegaderm on top of the tape already on the sensor?
Hmmm, maybe DexCom would have som suggestions? I know I’d be pretty upset if I had to get rid of a sensor after one day!
Yep Tegaderm works for me too. Put it over the whole sensor & transmiter and take it out at least an inch past the white tape that comes with the sensor.
Use an alcohol based medical swap over the whole area and let it dry about 5-mins before you insert the sensor, then apply the Tegaderm. You should get at least 8 or 9 days before the Tegaderm starts coming off at the edges. I then just patch it up or carefully peel it off and apply a new sheet.
I too, like Heidi, cut a hole in the Tegaderm before applying it to my skin. I use the sensor that I just removed to gauge the dimension of the hole to cut into the Tegaderm, but after a few times you do this it’s not that difficult to cut a hole of the right size.
I use Tegaderm 1624W which I bought off eBay in quantity at a very reasonable price. It’s 2 3/8 by 2 3/4 (6 by 7 cm) so slightly smaller in length compared to the white tape that comes with the sensor. So I cut a bit of the white tape and make sure that the Tegaderm covers nicely the white tape on all sides.
It looks quite complicated written down here, but it’s not that difficult to do. Takes me just a few minutes, and the Tegaderm lasts as long as the sensor, if applied correctly (no wrinkles in the tape and nice hairless skin…)
Ciao, Luca
Regarding accuracy, I am a bit math challenged, LOL. My sister reminded me that a 20 percent deviation would mean that if your finger-stick reads 100 and Dexcom reads 80 or 120, Dex is in the 20 percent range, BUT if your fingerstick reads 200, twenty percent variation on that higher reading would mean Dex could read 240 or 160 and it would still technically be within the 20 percent range. When Dex is off, simply recalibrate and Dex will drift a lot closer to your fingerstick reading. Assuming all is well with the sensor, that is. In the beginning, I thought a 20 percent variation would mean that it was always within 20 or 30 points of the fingerstick. Not so.
Don’t forget that the finger sticks also have an accuracy tolerance of 31 points. So if actual blood sugars are 100, the finger stick could be reading 69 and the Dexcom could be reading 120 and they are both right!
Then add in the 10-minute delay it takes for the blood sugars to absorb into the interstitial fluid under the skin, which is what the Dexcom is reading, it could be even further out if your blood sugars are falling!
The best way to test accuracy is to check when you blood sugars are stable. Before meals etc. when your Dexcom is indicating a nice straight horizontal line for a good 30-minutes or longer. It also wants to be indicating ideal blood sugar ranges between 80 and 180. Then do at least 2-finger stick blood tests to see if the Dexcom is close. Ideally it should be within 20% of the finger sticks. Take an average of the finger sticks if you have to or discount one of the results if you have to. If you have bags of free test sticks like I always seem to have, just do 3 or 4-finger stick tests and then you will have a much better idea which results to rely on and which to ignore.
It’s also worth remembering that your finger stick blood test meter also needs calibrating from time to time using the test fluid the manufacturer normally provides with the meter! No point questioning the Dexcom, if the meter is so far out, it is not worth considering.
What meter are you using to calibrate? As Chris pointed out, the meter itself can be very inaccurate.
I changed from the OneTouch to a WaveSense meter once I could do that and immediately saw a drop in my A1Cs, even though my Dexcom readings were about the same. I think that’s because the calibrations were much more accurate thanks to the WaveSense accuracy.
I use the PDM from Omnipod, which is a freestyle meter.