CGM Unavailable Alert/Spotty Graph

In the past couple of months, I have been CGM Unavailable Alerts later in the 10 days of my G6 sensor (in use with the Tandem). With the first two, I thought it may have been due to my transmitter being in it’s third month, but now I have started a new transmitter and I am getting this again. I called for a sensor replacement for one. I was able to drag another out to the end, but the readings on the pump were in and out. Now, with my new transmitter, I am disappointed to see this happening again. I still have a little bit more than three days left on this sensor. Is anyone having a similar issue? I have been on the Tandem/Dexcom for 2 years now and have rarely had this alert. I rotate the sensor around my abdomen and do not have noticeable scar tissue even with 35 years a T1D and 24 years on a pump and eventual CGM use.

Hi @parkerbe . I haven’t had that issue - at least not yet. I’m wondering if the problem sensors came from the same lot number? Hopefully you kept the package and can look it up.
Always call Tandem when you have issues - they will send a replacement sensor if yours fails completely, and even if yours eventually reconnects they might replace it as well. It’s a headache but you do want to get your value. You can also request a replacement online.

Beth @parkerbe, do NOT call Tandem with a sensor error as Tandem will listen to your story and then forward your call to Dexcom where you will wait again and retell your story. Call Dexcom from the USA at 844-607-8398 and choose option #1. Or even easier, log on to Dexcom and fill in the form requesting a replacement.

I’m uncertain what you are referring to when you say “CGM Unavailable Alert”. There are two principal occasions that your Tandem pump or secondary Dexcom receiver will not show a CGM reading:

  • Signal Loss: which shows on the t-Slim as a red hourglass symbol [and on Dexcom secondary receiver - phone - with words “loss of signal”. On the Tamdem, first make certain that the “signal post” on the pump face, to the right of battery is illuminated and that Bluetooth is turned on and that the pump and transmitter are within 30 feet of each other and neither device is being smothered. If you receive a CGM reading on the phone and not the pump, it is probably because a pump setting has been changed.
  • Sensor Error: this is the more common time a CGM reading is not present, and the most annoying. It displays on the pump as (—) and on the phone as “sensor Error” with an extended instruction. It can happen for two reasons, the first, is because the computer in the sensor transmitter senses erratic changes and won’t provide you with damaging information. The more common cause is the sensor wire is getting “pressed” or is loose and moving. Compression by leaning on the transmitter or pinched by clothing is frequent.

That is the technical stuff. Personally, I’ve noticed that my G6 sensors are of late providing me with more “sensor error” messages than any time in the past 4 years; one this month beginning day 5. The two other in the same box worked wonderfully - so it doesn’t appear to be the same lot number. The good news, if any, is that Dexcom doesn’t hesitate to provide a replacement.

Thank you @Dennis . I said call Tandem but that should be Dexcom. I sometimes interchange the two even after all this time, and should be more careful. Thanks to Dennis for that critical correction.

This may have nothing to do with your issue - but - I noticed there were often times when my sensor said “no signal” - usually when I was streaming TV. I checked with Dexcom - we have a wifi mesh extender in the house, and yes, this can interrupt the signal. I don’t know why, since my pump and sensor are only about 12" apart (on my body), but non the less, it does. Since I am not giving up streaming on TV, I just live with times I don’t have instant access to my BS. If we turn off streaming, BS readings return in a couple of minutes.

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I’ve had the same thing when I would wear it on my abdomen. I switched it to my upper arm. It works much better for me. I wear an armband with the pump next to the sensor at night. Doesn’t lose contact then. That’s just how it works for me.

I find that sometimes when I am sitting down and the sensor is on the left side of my abdomen and the pump is on the right side and has gotten worked around to the far right side I lose the signal. It doesn’t immediately reconnect when I move it to the left side, but it eventually finds it and reconnects. (I imagine your situation is not that simple, but it is a way I’ve found that the pump loses the connection.)

Hi Beth,

I had a box of sensors recently that I had the same problem with. I wonder if they are from the same batch? Unfortunately, I’ve already discarded the box, but it still makes me wonder!

Pam K.

I wanted to thank each of you for your contribution. I have read them with interest and tried a few things.
Terri, we had just cancelled our traditional cable account and started streaming many TV shows. This was an interesting investigation for my husband and I!
Dwayne, I love my arm too! But on my first sensor that went in and out, I called to get a replacement and one of the questions was if the sensor was on the abdomen, so I made sure to place the future ones (that continued to get the spotty trend line) on my abdomen. I now am on a new box and just changed out a trouble free one on my arm! I understand the G7 will be approved for use on the arm. This is, I think, a good thing.
Dorie, after years of use with Minimed/Medtronic (dealing with one company), I too have to retrain my brain to think about which company I need to contact with concerns. I too thank Dennis for the reminder to do that!
Again, thanks to each of you for taking the time to read and respond.