@bkh thanks for that explanation. I will send it along to my endo because we have all been mystified by this situation - which also happens to me occasionally. I’d assumed it was a calibration glitch but your explanation makes sense sort of I guess based on my complete ignorance of these processes…
Anyway let’s see what my endo has to say about this. Very interesting.
This happens to me when my insertion site bleeds. It’s so frustrating! When this happens, I need to have it replaced because it just gets saturated and ruins the sensor.
that seems to be what happened to me…about 9 months on dexcom and this was the first one to bleed
This happens to me often. I’ll wake up in the night with a 52 or some such. I’ve noticed when I roll over on it in my sleep I go low instantly. It only happens within the first few hours of a new sensor, so since I know that I don’t worry big I do get worried I just do a finger stick to reassure myself. The thing that’s bothering me is that every time I have a low the app doesn’t reflect it later. This is a screenshot hours after that 52. No wonder my dr thinks I never go low. Why would the app change that?
really strange…it sure is different for me, the app shows all my lows, even those that arent real lows, which makes my dr think i have way to many lows and i wish i could makr them go away
Welcome to FUD @SugarMona! I am guessing that your drops and recoveries are pretty fast and that the system is smoothing over them. If you want to read more about it, look for BillKast’s post in this thread where he does a good job of talking about the graph smoothing that Dexcom does.
I recently spoke with a Dex CSR (I usually just go through the app to report possessed sensors, but I’m pretty sure that I have a bad lot, as every single one of them has been crazy.)
So, this is what she told me:
So, I’m on a new one from the bad lot. Woke me up at 3 am, with LOW. Checked, 120. Calibrated. Seemed to be working this morning. Had a banana, but did not bolus, as I had a lot of cleaning to do. Next thing I know, Dex is showing 260 and screaming. Check, 50. Calibrate, have some sugar. 1/2 hr later, BG 70, its screaming LOW. After 4 hours of alarms and calibrations, its finally correct, but for how long?
So, basically, there’s great ones sometimes, and then ones I wear for a day, and report. Oh, yeah, and some CSRs are clearly just reading from a script.
What is quite amazing is that I think we at FUD have evidence of every one of those assertions being wrong. It is not often that a company goes to the effort to make a script where everything they say is incorrect. I may be crazy, but I think I have seen Dexcom advertising with people wearing them on the arm.
right…how long? Your experience seems just like mine. the other thing they have told me is that I just need to wait it out and eventually it will settle down…so how long is it unsafe to have totally inaccurate numbers…they didnt have an answer for that …nor could they answer how many finger sticks/callibrations they think is acceptable on one day, when I told them I was at 20+ in 12 hours they seemed to feel that was ok
How long have you been using the g6? I originally wasn’t told to report bad ones, so I spent a lot of time driving myself insane. Now I opt for the email contact, unless I feel like its something they need to know about.
A few tricks that have really helped me, all of which I learned here:
Pre-soaking really helps me. When I feel like the old one is approaching its inevitable slow and painful demise, (usually around day 7) I slap another one on.
Find the placement that works for YOU. Abdomen has never worked for me, mainly due to scars, and that’s where I bolus.
Hydrate! For me, that’s at least 2L/day.
Don’t let the Dex be your sole meter, ever. You’ll learn when to trust it. Some will right themselves, others are possessed. It would be great if it was actually like the commercials, but its led me down the wrong path a few times when I forgot my regular meter.
I haven’t read the replies yet but wanted to just jump back on here to say WOW! I have NO IDEA how this could have happened but about 30 min after my reply to this issue the exact thing OP described happened to me BUT not a new sensor or transmitter. WOW. Well played universe. Currently my Dexcom is down. 
going on 9 months for me…the last few have been the worst for bad readings etc…and I still think its the 3 month supply i got were all from the same lot and defective at least to some degree.
@Chris Yeah, it was kind of surreal. I couldn’t even get mad about it, was just laughing for hours after.
sorry you are having to deal with it too, It is new to me for this to also happen on a sensor that is not new…not fun 
BKH - thank you so much for posting this clear explanation. I need 12 hours for the sensor to settle, otherwise am battling false lows and Dexcom SCREAMING at me, inevitably in the middle of the night! Thanks again - Jessica
You will only get the company line when talking to a CSR. You’re not talking to and most likely will never speak with a dexcom expert; just someone they pay to answer the phone which they provided some basic training and knowledge items to help with the calls and questions.
This is another reason why I stopped wearing the Dexcom. It became much too complex in their role to seek a profit. Every time I had a problem, the solution was always “change the needle” which meant an additional hour of my time and an added insurance charge, plus my husband had to be available to help since I couldn’t do it alone. Eventually insurance only covered enough needles for a year, without extra replacements for problems.
do you mean change the sensor? there is no needle to change.
thus far dexcom has always replaced the bad sensors at no charge so no need to worry about insurance
We can only hope that the new G7 system will address some of these issues. Like you, with all the glitches that Dexcom has, it’s only a matter of time before some person doesn’t get the important warning that they should have gotten because the Dexcom was being squirrelly.
