I am a new Dex user - for about 2 1/2 months now. I have had a lot of ??? escepially at night and I think it is related to stagnant interstitial fluid and it being unable to read. Once I am up in the morning and moving around, it works again. It tends to happen for the first couple of nights. ALso - I have had 2 arm sites in now - and it happens more often with these - not as much when I have used my belly. I have an arm site in now and put it in on Saturday. The last 2 niths (first 2 nights of the sensor) have been with frequent ???.
It always amazes me how things work so differently for all of us. My arms are most accurate for me and that's where I have fewer problems; legs are good; abdomen is worst.
My experience has been that the ??? seem to show up (1)When I'm trending up or down really fast like the Dex can't keep up and gets confused so it just gives up for a while, (2)When a sensor is about to die or is dead (usually this happens in the 2nd week of a sensor),(3)When my receiver has been sitting too close to my cellphone, and (4)When I accidentally took meds that have acetaminophen (made that brilliant move today!)
I just got a dexcom as well. I put in my first sensor and all I got was ??? so I called the company and they went through some possiblities with me and when we could not come up with a solution to the problem they told me to switch to a new sensor and then they sent me a new sensor for free. I would advise you to call the company. If they cannot figure out why it is happening then they will send you a new sensor so you have not lost any money. (by the way mine was in my leg and they still sent me a new one)
FWIW, we're all a bit different. Last two sensors have been on my arms, and I got no '???' until the first died after about 9 days. I am now on day 8 of the second one, with no errors or anything yet (knock on wood). Numbers have been real good, but no better or worse than inside of my thigh, or up on my tummy (all locations seem pretty much the same to me). I don't like using my tummy so much -- my skin gets real sensitive. And many of the sensor injections there have hurt as well...
The only ??? I have got are after a couple of weeks. This is usually when I know it is time for new one. I always go with the belly site, and have gone through about 30 sensors with no problems. Does any one who uses the upper arm site sleep with their arm behind their pillow? Does this affect the life of the adhesive? I've wanted to try this site, but haven't because my are bent behind my head when I sleep.
I sleep with mine under my pillow... and over it... and sideways... all which ways, honestly. No real issues here (that I can tell, anyways).
Recommendation for Error "???" is to wait for the Receiver to clear and request you to input Blood Glucose reading when the Reviver request. This is the recommendation from DEXCOM when I receive this error.
I just started on my Dex this past Friday. My first sensor worked well. I put it on Firday night. I woke up and it was working well. Got in to shower and when I stepped out and looked at the Dex, i had "???." I just removed it and used a new one and have had no problems since.
When I get the ??? I always enter 1 or 2 BG's. If after an hour or so it's still there or comes back, I stop and restart it. That sometimes works. If not then your only choice is a new sensor.
I don't worry too much about the ???s. Sometimes the next time I look at my Dexcom, I've got a reading. If I get a high frequency of ???s, it's usually an indication that time is running out on that sensor. (I try to use sensors for two weeks.)
The ??? error is a result of the sensor being placed too close to the pump infusion set. I learned this from the Clinical Education Specialist assigned to me by Dexcom. She was totally right - as long as I insert my set more than three inches away from my sensor, no ??? errors appear. Hope that helps!
I have noticed moisture under the transmitter when I get the ???. My first step is to take the transmitter off, wipe the bottom of it with an alcohol swab, and click it back into place. This usually cures the problem.