Dexcom G6 best practices

I started out great on the G6, with decent accuracy, ability to restart and stretch sensor life a few extra days, and trouble free CGMing. The good times lasted about 5 months and came to a halt with my last 4 sensors. Each of these would not go longer than 8-9 days. Their death throes include sensor error messages lasting 1-2 hours, unexplainable rapid BG drops (similar to pressure lows but ending in sensor error) and unpredictable usefulness of the CGM over its last day or two.

I suspect the algorithm is at fault. I never had these types of issues with G5, and was always able to keep it going with strategic calibrations, a good tape job, and crossed fingers.

I am ready to try any suggestions regarding code vs no code, calibrate vs never calibrate, and what to do after a 1-2 hour sensor error (I’ve tried calibrating every few hours after a dropout and that seems to help for a half day or so).

Rather than post the play by play of my failed attempts to get 10 days out of these sensors, I’d enjoy hearing your best practices. Thanks!


I have found it to be more accurate when I do NOT enter the code at startup, and instead do calibrations once or twice a day like it was a G5 instead of a G6. And I also calibrate it when it is showing me a silly number.


I second this. For Liam, we’ve had MUCH better success not entering the code. The numbers have been more accurate because the CGM allows me to calibrate and or adapts those numbers more quickly.


Thanks…I have always used the code and have not had accuracy problems. The problems I’ve had are sensor death at day 8/9 with dropout sensor errors preceding by a day or so. After these dropouts the BG readings are sometimes off, sometimes pretty close. On the sensor I’m wearing now, I had a dropout of about one hour today (Day 8) and calibrated a few times during and after the dropout just to see what happens.

I’m wondering if “no code” usage would avoid these premature dropouts and sensor deaths? Will give it a shot on my next sensor.


Sorry, my bad. I didn’t properly put your post into context.

I saw mention of “unexplainable rapid BG drops” and talk of the algorithm and mention of “code vs no code” and “calibrate vs never calibrate”, so I just got the wrong idea about it being an accuracy issue.

I do not think code or calibrating would have anything to do with sensor errors.

But on the plus side, if you get 8-9 days out of it, that’s totally bonus. They still gotta replace them, regardless of if they last only 1 day or 9 days. :+1:


Yes they happily replaced the last 3 and I doubt that today’s sensor will make it to 10 days. The problem it causes for me is unpredictability…wondering where I will be when the sensor finally dies. I’ve been trying to work my sensor schedule around Day 1 (accuracy is not so good first 24 hours unless I presoak) so I am not dealing with inaccurate CGM alarms on certain days. Might be the impossible dream but it worked OK for 5 months and now…not going according to plan. Hockey tonight and I have no idea of this sensor will be false alarming, dead, or ???.

Has anybody done a comparison of “code-no calibration” vs “no code-twice daily calibration” for sensor longevity? I might end up doing that.


I’ve been going with the concept that 3 hours of cumulative sensor error dropouts causes me to no longer trust that sensor, and I call Dexcom for a replacement. I have no idea if they log into Clarity to check on that or not.

Anyway for the record, here is an example of the “precursor dropouts” on Day 8 of my last sensor:
And here is the dropout that caused me to give up on the sensor and replace it on Day 9. I was getting on a 6 hour redeye flight in 12 hours and decided I did not want to do that with a sensor that was going off the rails.


I don’t recall the number Dexcom told me, but I think it was something like that. Like if your total “no readings” time exceeds X hours, Dexcom said you can get it replaced.

Is 3 hours the Dexcom requirement, or your number?


I think I heard that here as Dexcom’s number but not sure. On my last call they don’t ask for much info (they did not ask how many hours it had dropped out). It seems like replacing G6 sensors has become fairly routine for the call center.


I’m relatively new to the g6… I’ve only had one sensor that I really considered to be a fail and even it lasted 10 days and was restarted for several more… but I definitely witnessed the nonsensical drops——- eg steady at 100 for an hour then all of a sudden reading 50 and strait down…and sensor errors…

Don’t really know what causes them to be bad…

I find myself ending up in the do not calibrate camp after initially starting out in the calibrate a lot camp… though the issues you describe aren’t related to calibration as you point out.

My main complaint has been the skin reactions, other than that it’s been an appreciable upgrade from the g5, and with not having to calibrate is and check my bg manually has actually made diabetes a smaller part of my life— which is a big deal… so if I can figure out how to eliminate the skin reactions (just ordered some colloidal bandages to put under it) I’ll be quite pleased with it


I haven’t had an issue with the sensor life. I’ve had a couple crap out early, but not enough to cause grief.

My biggest gripe is poor accuracy the first 8-12 hours.


On my last call back from Dexcom, the rep said just replace it if the sensor error happens more than twice a day. Even if its just for an hour. For me, I know its a bad one when it gives up for 2 hours and 59 minutes, then miraculously comes back just under the magic 3 hour mark. Yes, they definitely know that they will be replacing a lot! If it happens with 3 sensors in a row, I request a new transmitter…


@Mariethm, I didn’t know that, thanks.

@John58, I experience what you are going through, too. I see on your graph that you experience a steep BG drop prior to the sensor error. This happens to me,too, when I have a steep drop, say, +20 in 5 minutes. Usually the sensor will start back up in 30 minutes or so as long as my BGs stabilize. Once this happens though, it seems like the sensor is more likely to fail eventually before the 10 day period. It is frustrating. I think there must be an issue with the algorithm. I try to not have any steep drops or rises, but some days it is just not controllable.


I guess that’s part of my skepticism about the G6…not sure I really had a steep drop. There’s no reason for those steep drops in the middle of the night. I think the algorithm might be confusing a pressure low (very common with the G5) with steep drops., causing it to shut down and go to sensor error.

My current sensor is on day 8 1/2 and has already accumulated more than 3 hours of sensor errors. I decided to hit it with frequent calibrations, will see how it does. Played hockey and it seemed OK. Got home and calibrated it: G6 BG 98, Contour Next 132.


I like that idea! Would rather go back to the G6 good times but a new transmitter would be nice.Maybe that will solve the issue?


Hint: Remove the Original Dexcom Adhesive Tape as soon as it starts to peel off, e.g. on day 7. Cautiously cutting around the sensor while not applying force to the sensor (make sure it sits tight and does not budge). Then use an alternative adhesive patch (e.g. ready-made overpatch or self-made from a roll) and fix the sensor/transmitter again tightly to your skin.

Make sure that the sensor has some compacting pressure from all sides → this is essential for avoiding sensor errors: Loss of adhesive contact => sensor errors.

This concept works fine for me, always getting 15++++ days out of a G6. After another week or so you may need to remove the overpatch and apply new tape again. Good luck!


Not sure what this means but my guess is: lap the tape up onto the edges of the plastic edges of the sensor by a wee bit? Will give that a try too, thanks!

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Something to think about on the G6.
I know for ME, depth of the sensor itself makes a difference.
I push the insertor against my skin so the adhesive sticks well, then I lift off with the pressure so that I get a small amount of air space between the insertor and the sensor itself.
This gives me a better angle for ME.
Point, maybe the angle of how the sensor gets inserted into your skin could also be affecting this? I would try a few different scenarios on this as well.

Btw, I am in the almost never calibrate group.
I presoak my sensor, usually overnight, but at least for a couple hours. I have had to do a quick swap a few times and started a new sensor immediately. But definitely some odd readings for the first half day.
I also run almost everyone of my sensors for 14 days so I can keep my schedule that I like. New sensors starts presoak Saturday night, swap transmitter in the morning for a new session.

I really wish they would offer two separate versions of the adhesive. Nothing affects my skin, so I would really like to have stronger adhesive.
And a second option for those who have issues/irratations with adhesives. There will always be a group here that needs a better solution for them.
And not having to make a ‘one size fits all’ kind of thing where everyone seems to lose in the long run.


I’ll try that next time, although I’ve never felt like my sensor seemed wiggly or loose. Usually I push straight into the flesh to get good adhesion and then I push the button. The 4 sensors that failed early were on upper arm (2) and belly/side ish (2). Three of them had travelled with me to Kauai as spares, going through airport X-ray several times as well as the agricultural X-ray they use there…maybe that screwed them up?

Last night I gave up on my G6 sensor (at 9 1/2 days) and decided to start a new one. Used one of the replacements recently received from Dexcom, to take the possibility of a bad lot out of the equation. Did not have time to presoak but have been getting good accuracy today, 14 hours after starting it.

In response to @emp00 above, I used (1) skintac on my alcohol scrubbed skin, overtaped (home made using Grif tape) using more skintac with a tight overlap up the edges of the sensor base. This is an upper arm installation, pretty standard for me in terms of no bleeding, no pain, around the back a bit to minimize inadvertent bumping.


My comment on how I insert is more about how I think the angle of the sensor wire works in my skin.
At first I was pushing it against my body when inserting. That didn’t work well.
Then I was almost no pressure, that worked better, but still needed improvement.
Very slight pressure AWAY from the body is what works best for me.

I like to clean the skin, apply skintac to the sensor before insertion, let it tack up. I don’t reapply skintac until day 10 ish, if I need it.
I never really got good results from the over patches. I think having the larger surface area of my skin causes more issues rather than fewer.