Sensor failure

I had a weird event last night. Around 1pm my sensor read 130 (I was asleep). Around 1:30 the receiver stopped getting the data, even though it was almost right on top of the transmitter (within 6"-still in the same place I left it when I went to bed). Then at 3 am I was awakened by the standard low alarm (<55) with a reading of 47. I had received no alarms in between for rapidly falling BS or for my regular low that was set at 60. In fact, there were no data points received by the receiver between 1:30 and 3:00. Anyone have such experiences? Sure wish the communication between transmitter and receiver was more dependable. I’m thankful that the default alarm worked despite the lack of interim data. Any advice from long-time users?

I have this problem occasionally with new sensors, or ones that are placed on my body such that I sleep on the sensor itself (like on my arm - I sleep on my side). You are probably seeing the ???, rather than the antenna sign? For me, even these sensor sites that I sleep on improve over time and this usually stops by the second or third night. If it remains a problem, and you think site location might be the cause, you should probably think about finding a different place for the sensor next time, otherwise just give it another night and see what happens. You can also call Dexcom - they might consider it a bad sensor if you were not receiving data for more that 3 hours and just send you a new one.

Thanks for the advice with dexcom. I never saw any ???, though they may have been there-I was asleep. Site was only 3 or so days old, but it is on my abdomen & I sleep on my back, so I couldn’t explain it based on positioning. I’m guessing that it must have been some weird thing like my arm getting in the way or something. How does one know when the transmitter battery is beginning to run out? I have been using the cgm almost constantly since late May of this year without too many troubles so far.

I’ve only had mine a few months longer than you so I wouldn’t know about the battery thing.

You might also lose signal if you keep the receiver under your pillow and lay on top of it. The radio waves that the transmitter produces can’t go through your body - they are too weak for that. So if the waves can’t find a way to the receiver without going directly through your body then there could be loss of transmission that way. You can try keeping the receiver in a different location, but if it usually isn’t a problem, than last night might have just been a fluke

There are so many things that can cause your problem. Have you searched through the group discussions that have a lot of useful information? One possibility is that one corner of the transmitter might not be fully snapped into place. There would be false numbers or, perhaps, no numbers if that occurs. I have a lot of scar tissue on my upper abdomen from 61+ years of injections. I was never told I was supposed to alternate sites and had never heard about problems caused by scar tissue. If the sensor is placed in scar tissue it will not give good results, and may even fail to produce numbers consistently.There are other possible answers, but they have been posted many times in other discussions here. I’ll see if I can find one and give you a link.

There are many older discussions that contain very good information, and you might find a solution to your problem among them. Here is one old discussion:

I have had my SevenPlus system for about 14 months. Dexcom contacted me after about 13 months to get a replacement. The system is waranteed for 12 months. It does seen like I am having more instances of the receiver loosing contact with the transmitter.

My insurance covered a new system in full, and it was delivered today. I haven’t even openned the box yet, unlike my first system which I couldn’t open fast enough.

I too lose communications during the night sometimes. Bob, do you have an active alert for Out of Range? If you don’t try setting one so you get a notification if your transmitter and receiver are not communicating.

Thanks for the tip, Richard!

I do have the out of range alert turned on to both vibe and beep, so I’m not sure why that did not wake me up, perhaps it was in range, but had the ??? message without a beep. Fortunately, the low alert did wake me, but all that it shows on the downloaded data is a lack of data points for that time period between when I was 130 and when I woke up low (about 1-1/2 hours).

Not to hijack this thread, but it got me thinking: how often are other people having sensor failures?

I’m not talking about periodic missing connections overnight or the ??? that resolves itself, I mean getting a “sensor error” or “sensor failed” message that forces you to trash the sensor and start over after only a few days.

I seem to have a problem about every 1 out of 3 sensors, although I have been using the Dexom for only about 6 months now. My problem seems to come from not having enough fat or tissue, because when I pull a failed sensor out it is curled or kinked at a 90-degree angle from contacting muscle. And this is very uncomfortable, but I try to go with it as long as I can. If I have a good sensor I can stretch it out for 14-15 days, so with the failures I figure it all evens out. But it is still frustrating, and I wonder if it is normal. When I call tech support they don’t sound surprised or suspicious, even though I am calling every 2 weeks or so. What is a normal failure rate?

I’ve had my Dex for maybe 9 months and I’ve never had a sensor error message, but I don’t have the same Dex-hitting-muscle problem as you…I must be better insulated…

Sounds like I started on the Dexcom a little while after you (around end of May). I have had at least one - maybe two-of the sensor error screens that you mentioned, and just like yours, when I pulled the sensor out it was already kinked-up on top of my skin. I do a lot of trail work out behind my house and when I saw the kinked wire, I remembered getting a jab when I had leaned over once. That made me feel like it was related to my own lack of awareness of how much the site required protection from movement. Perhaps like our ClumsyChemist, though, I also seem to have sufficient padding above muscle. Since that event I try to bend my body before placement while choosing a site to learn how the bend is likely to impact the sensor. Low spots are not good for me, because the surrounding tissue, can pinch the sensor when I’m bending over, lifting it out of the site. So far so good with this new plan. Looks like you are active from your photo, so maybe your activities are contributing to loosing the site. Good luck!