Dexcom G6 false fall rate alerts

Question for G6 users - Do you ever get false random fall rate alerts when your sugar is actually steady and then it seems to fix itself within the next few readings. It’s happening quite a bit lately and it’s been with different sensors as well. My blood sugar is not falling as fingerpricks confirm my sugar is steady. It’s also not after a shower or exercise or ‘compression lows’ as it’s during the day and there is no pressure on the sensor as I know those situations can cause readings to be a bit off for a bit. Any thoughts why dexcom thinks sugar dropping rapidly when it’s not ?

I have had the random nose dives happen a couple times with sensors on their first or second day.

Maybe just maybe it is more likely to happen when there was a small amount of blood on sensor insertion.

I’ve been using the G6 almost two years and the nose dive has happened a couple times each on maybe 4 of the 60 sensors I’ve gone through.

The nose dive has some similarities to a compression (false) overnight low from rolling over on to the sensor. But the dive seems to be steeper and happens when I’m not lying down.

Of the 60 or so sensors I’ve gone through, only one of them did not “straighten out”. That one sensor had lots of blood on and after insertion. Total gusher.

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@Amelia3 I am new to the G6 still working through the first 9 sensors. They are all the same lot number, 5284426. I had problems with sudden false ramping down and occasionally after a sharp drop losing signal for 25 to 35 minutes. Dexcom replaced 3 of these sensors all different lot numbers. 2 have worked flawlessly the 3rd is in my “D” drawer unused.

The first sensor to fail taught me a real lesson. I stupidly treated a low that wasn’t happening ending up hypoglycemic. I have sense learned to finger stick if I have any doubts. I really hope the next shipment of sensors is a different lot number.

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I’m having this problem now. Brand new sensor has kept me up 2 nights in a row. I’m starting to get crabby.

It’s constantly jumping 30-40 mg/dl. Not something I’ve ever seen on a new sensor before. I didn’t meet the replacement guidelines yesterday (at least not the ones I know), so hopefully today is the day I can replace it.

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I had this happen with one sensor. I fought with it all the way through. I took it off and it looked normal, no bend in the wire.
I went the 10: days so I didn’t get it replaced.

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Yep. You are right. The dive does seem a lot steeper than the overnight ‘compression lows’ . I’ll keep an eye on it. Hasn’t happened again on this one … yet.

Frustrating isn’t it. I always check with a fingerprick when these things happen. I’ve learnt not to trust it when it’s ‘dropping’ and I don’t feel like it is.

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Yeh. If it keeps happening insist on a replacement. I love dexcom but it is technology that fails sometimes so we should get a sensor replaced if it doesn’t work properly.

Yeh. I often persist but now I think if it happens more than once or twice a session I’ll get a replacement sensor. The dexcom rep told me once sometimes the sensor wire moves slightly and throws it all out of sync.


As far as I know, the eversense still requires 2 calibrations per day. I’ll consider it when they can eliminate calibrations or at least reduce them considerably.

It hasn’t happened often, but we just had a sensor that acted this way. We removed it and I called dexcom to ask for a replacement. It’s particularly annoying with control iq running.

I cannot tell you how many times I’ve had false sharp drops in BG readings during the first 24-36 hours of wear. When it happens at night — not because of compression— I am very disturbed by being woke up. In January I replaced 5 consecutive Dexcom sensors in a row, 3 of them due to inaccuracies exceeding 50%. This false narrative by the company that you do not need to do finger pricks is absolutely wrong and dangerous to advertise to new potential users on TV.


Most of the time I don’t need to calibrate mine. It stays very close to my fingerstick readings. When it’s off. It’s off an doesn’t work at all. That less than 10 percent of the time

Ok. Here goes. I have found the drops occurs most often after eating a meal even thou I bolus Dose for that meal.
For me I get a rapid clump. Then it drops after reaching what ever high it’s going to have.
Even thou Dexcom say no finger sticks I still calibrate at least 3 times a day. It not that I don’t trust dexcom I’m am just try to stay on top of every thing…


If you intend to calibrate it. You might want to run it without the code. Because the calibration is temporary when you use a code and it reverts to factory calibration pretty quickly

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Can you tell me why you think this? Have you read this somewhere? This isn’t my experience (nor I doubt anyone else who does restarts and sees the massive difference calibrations make). I’m always so confused when I read this.

If it reverts, why are we successfully able to change it 100+ mg/dl, and have it stay accurate for the duration of the sensor life without having to continually adjust it that massive amount again and again?

I got this information from dexcom, on a troubleshooting call They told me that if I calibrate a sensor that was started with a code, it will revert to the factory calibration within a half hour. And that you can start with no code and it will not revert.
You can also start with no code and calibrate and then ignore cal requests after that.
So there are a few different options.

I notice if I calibrate it more than 100 points, it never comes back right and the sensor is lost.
This was confirmed by dexcom. They said if it is way off past the first day, there is something wrong with it. They never were specific to what way off means specifically.

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I have also had fast drops and rises when starting a new sensor, three or four times in 2021, with the newer lots of the G6 that shipped in the new packaging. I was very tempted to pull them off and start a new sensor and call for a replacement … But after a couple hours instead, I entered a calibration and it was like using the paddles to restart the heart rhythm , LOL. I followed that up with the second fingerstick a couple hours later, and if it’s a good match, I don’t actually enter that second calibration into the Dexcom , but it does give peace of mind I need.

I’ve not experienced any automatic “resets” to factory calibration after hours, or days, on my coded sensors . On the contrary, after the issues I had with those erratic sensors, I’ve made it a practice to do a fingerstick check a couple hours after each new sensor. I found some to be 40–50 points to high (like reading 160 vs. 110) but the calibration fixes it, and it stays fixed. And if the fingerstick matches of course I do not enter a calibration.


Its been my experience as well that a sensor started with a code will accept corrections and those corrections “stick” for the life of the sensor. I’ve developed the habit of using my BG meter once a day (when I wake up) and calibrating when the meter and the G6 differ by over 20 points. More often than not, zero or one calibration per sensor is all that is needed.