Dexcom has been inaccurate lately

Whenever or for whatever reason a sensor fails, Dexcom must replace bad sensors. As long as you “report” the sensor was in your abdomen. Some of us find more reliable readings, and fewer failures, using an arm or hip. Use the form to replace failed sensors on this page:

Whenever or for whatever reason a sensor fails, Dexcom must replace bad sensors, at least on the US. As long as you “report” the sensor was in your abdomen. Some of us find more reliable readings, and fewer failures, using an arm or hip. Use the form to replace failed sensors on this page, and indicate the sensor location was abdomen:

Like my last post, we are finding the Dexcom not very accurate. So disappointing. With my son’s experience, I would never connect to a pump.

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I have only occasionally had significant sensor problems. A couple of things that have helped me out. One is that I believe movement of the tissues around the sensor filament leads to inaccuracies. I am somewhat sedentary except for treadmill workouts and my numbers are usually dead on if I wear the sensor on my abdomen. If I put it in a thigh or arm, invariably it will fail at around 7-8 days. I got 25 days out of the last sensor BTW. Second, too many calibrations leads to problems. I find the first 3 or 4 readings are often off but things quickly settle down. Trying to calibrate during this period results in problems.
Additionally, keeping the sensor and pump in close proximity seems to help. I know it shouldn’t but it seems my control is better if I keep my pump on the same side as sensor.
I use the control IQ and my last HGBa1c was 6.5. time in range 80% so things seem OK.

I am probably not the best person to answer this one as I don’t know.
I am using the Tandem IQ and haven’t tested once to confirm the Dexcom. I have tested a few times during warm ups if I want to eat, otherwise, I just don’t test anymore. As far as how accurate it is, I am still here working everyday. The pump just does its thing and I live my life. I have not had any issues with blood sugar control. As a matter a fact, my time in range is better than it has ever been and I just don’t think about my diabetes much any more! I mean I can go all day and never look at, except when I am eating.
That being said, the accuracy is not an issue for me, I have started having skin reactions. I have been pumping since 1990 and using some kind of CGM for a long time (Minimed ones first☹️). I have never had any problems with adhesives. But the last 3 I have had on my arms have been swollen, with bumps and itchy when it comes off. One of my coworkers just started using the Dexcom G6 with her new Tandem (which she also loves!) and she said the adhesive has been just chewing up her skin. Just wondering if anyone else has had this issue or if it’s just me. Of course some might just be how darn dry things have been here in California and my skin is screaming for more moisturizer!

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@Sally7 The last few sensors I’ve used have left redness, That looked bad when I first pulled them off but went away quickly. But this last one left some uneven skin tone type of redness that is still there from 4-5 days ago. It’s not anything bad, but I have had no issues previously. I use Skin Tac and I notice the last sensor I really had to peel off of my skin, usually it’s much easier. I’m wondering if they did an adhesive change?

I started getting reactions to the Dexcom tape a few months ago. I haven’t ever been allergic to an adhesive before so don’t know why but I started using Flonase on the site first, letting it dry, lightly wiping it off with an alcohol wipe and then inserting as usual. Seems to work pretty well and doesn’t affect adhesion.

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I don’t actually believe we had a run of bad sensors, they were from multiple different batches sourced from different places, and we live in a cool climate. Given that the problems started with a new transmitter, and ended when that transmitter failed at about 5-6 weeks old, I’m fairly convinced the issue was with the transmitter all along.

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Makes me wonder if the transmitter is often the problem with these ‘runs.’ Maybe that’s been the problem all along.

I was having problems in the hot weather, seems to be settled down, except for a failed transmitter lately that had me frantic, and it took them a week to get me a new one. I found that yelling at Dexcom didn’t work that well. Getting my clinic to yell at them, that worked.

Re accuracy: lower abdomen has been better than legs or arms. Except for the time I hit a blood vessel and had a bruise the size of my hand for weeks. I do a finger stick every time I change sensors. I put the pump insertion sets on upper abdomen, and Dexcom lower, carefully rotating around a semi circle. It’s better if my phone, where all the aps are, is close to the pump - my trainer suggested 6". So it’s not perfect by any means, but better than finger sticks and multiple injections, in terms of getting better glucose control.

Dexcom CEO Kevin Sayer did a podcast about a month ago where the subject of adhesive changes came up.

They did change their G6 adhesive earlier in the year and have had far fewer sensors falling off. At the same time there had been an increase in reports of skin irritations and they are studying this issue and are looking at several alternatives.

See 22:20 of the podcast below


They have adhesive remover for skin tac!

I use the overlay patches with the g6 and I use tegaderm on the infusion set. I spray loads of alcohol on insertion areas to remove all adhesive much easier and rarely ouch!!

I use a generic one time use skin tac thing and I squeeze excess fluid off since they are sooo soaked. I apply the devices and wait a few moments before using the skin tac stuff on top of the white adhesive surrounding the sensor and the infusion set. I soak it quite a bit so it absorbs. I wait again and add the overlay patch for the g6 snd the tegaderm for the infusion set.

Mostly I only use the skin tac for the CGM since it must stay longer snd im clumsy so I’m pretty good at running into things knocking it off!!

Another method that a CDE suggested was using very thin tegaderm or other clear film adhesive… place that on your skin and do regular insertion process. The g6 will typically read fine. It’s putting stuff on top or skin tac type products over entire area injecting through that can mess the sensor up. Apparently the adhesive tape typically works because it’s not a liquid that must dry and who knows. It just works.

IV 3000? Or it’s called IV 4000 … something like that is a very hypoallergenic clear film adhesive. It’s a bit pricey though. I’m hypersensitive but not enough to need that but I have friends with extremely sensitive and potential anaphylactic reactions to many standard adhesives but can use the IV 4000 stuff.

I do a lot of aquaphore or similar after removal and cleaning to try and keep my skin happy.

I had MRSA last year and I believe it spawned from insertion stuff. Endo said she didn’t think so but I’m pretty sure it did. That sucked!! It wasn’t severe but I had some pretty bad boil things from it.

Anyways, I wish the CGM snd pump companies offered hypersensitive skin friendly options. Maybe one day they will if enough people complain!! Guess it would be another step in FDA approval though so that’s likely why they don’t provide these options

My really low errors…more than 100mg/dl were on the abdomen below the belly button. I stopped using the abdomen about 2 months ago. Much better results for me.

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My experience with Dexcom G6 sensors is they have been accurate (that is, reasonably close to my meter tests) on days 2 through 10. I have had some inaccuracies during the 1st 24 hours of a new sensor, though the last two were accurate from the get-go. Regardless, I meter-test several times during the first 24 hours, and if it is quite far off, I increase frequency of tests and calibrations. When it is really off, requiring significant recalibration, it can go into error, which I think is a design flaw in the meter app/firmware. It should just accept what the re-calibration values are.

After the first 24 hours, I will test 1)like the manual says, whenever the CGM reading does not match what I feel; 2)every 3 days when all has been ok.

I suspect there are a lot of factors that can lead to inaccurate readings. I personally always put the sensor on my abdomen, either to the left side or right side. I also always put a patch over the G6 adhesive (pre-cut for G6 sensors). I use FixiC patches. That may help keep it accurate, possibly making sure it is not disturbed, for example, while sleeping, though I have no way to prove that.

In any case, my experience is not that Dexcom CGMs are getting less accurate than they were. But, every body is different – different shape, skin, oil content, movement.

I had read about Dexcom sensors failing from bad lots but never experienced it until this morning.

I had replaced a sensor late yesterday and was woke up in the middle of the night by emergency medical people and my Dexcom transmitter and phone were both indicating a severe low under 40. My daughter had called for help when the alarm went off on her phone. I can’t hear the phone with out my hearing aids.

The low numbers surprised me since I didn’t feel that low so I did a finger stick which indicated a blood glucose level over 200. I repeated it and also got the same reading so figured it was an equipment malfunction. Then I noticed my receiver was indicating a reading of the same level. But then the screen went blank and showed the red triangle with the error message of sensor failure.

I called Dexcom for advice on what to do and after a 10 minute wait I got a very nice kind and helpful person who indicated I needed to replace the sensor. I used my last sensor and went back to bed.

A few hours later I woke up and saw the same error message and looking back at the readings it looks like it began working for awhile before it showed a sharp decline and then quit.

I called in again to Dexcom with the number of the first customer service gave me to avoid the 10 minute wait on their phone tree and got a new representative and repeated my problem.

The second representative sounded like she was from a foreign country from her accent but was not helpful at all. Both sensors had the same lot number. After several minutes of frustrating discussion she finally agreed to replace the second sensor too but indicated they have no way to speed up delivery so it will be 3 to 5 days to get a replacement.

I have been using Dexcom CGM’s ever since they came out and remember in the past when they used to have very good customer service and were able to replace things very quickly.

I have never had two sensors fail back to back in a few hours. I have become very dependent upon using the G6 to monitor and adjust my blood glucose level and relying on finger sticks for the next several days will be a frustrating experience.

That is a terrible story. Clearly you got 2 bad sensors and it probably was, as you are guessing, a bad batch.

What I do is not condoned by doctors, and I would not recommend this to people unless they are lucky to sense when they have gone very high or low.

Every so often, I simply restart my G6 sensor and use it another 10 days. This builds up a small inventory of sensors in case of earthquake or other problem, but also in case of what you have just encountered.

My meter tells me my sensor is absolutely as accurate the second 10 days as it was for days 2-10, and somewhat more accurate than the first day.

I am sure Dexcom will block this ability in their next version, and either we’ll find a new way, or not.

I use the simple method of removing the transmitter using a test strip to not damage the sensor, keep it out 30 minutes, then do a normal new sensor routine. Works every single time with G6. I immediately calibrate using a meter once the 2 hour warm-up finishes. That’s all there is to it. Removing the transmitter was tricky the first time, so a video (there are many) can be helpful.

Again, only do this if you feel comfortable and you double-check with the meter if you are not sure about accuracy.