Dexcom g6 calibration

I will be receiving my new Dexcom g6 in a couple of days. Not having to calibrate is a big advantage. When using the Dexcom app on my iPhone will I have to calibrate one time per day? I’ve been reading the user manual and it seems to me this is the case. So, if I use the Dexcom receiver I do not need to calibrate but if I use my phone I do?

hi @synstokesyahoo-com Synthia, G6 allows you to manually calibrate, but it is not required to operate the system, provided you enter the sensor code during startup.

G6 will force you to calibrate if you lost the “sensor code” - it goes like this:

“If you didn’t enter a sensor code during setup, you must calibrate your G6. After sensor warmup, you’re prompted to calibrate twice. Then you start getting your G6 readings.
You’ll be prompted to calibrate 12 hours later, and again 12 hours after that. For the rest of your 10-day sensor session, you’re prompted to calibrate once every 24 hours.”

the G6 could do a medtronic guardian “dance” if you are manually calibrating it and that is: if the sensor disagrees with your manual calibration by too much it will throw a code and kill the sensor. Manual calibrations (from personal experience) needs to be done with your sugar flat-lining or it just doesn’t work well.

G6 will allow you to calibrate if you want to: if you are feeling low and your finger stick says your low but the G6 does not… or something like that. There is a procedure and you can manually calibrate. I can’t tell from the user guide if you manually calibrate if G6 will ask you to continue to manually calibrate every 12 hours, that one is not in the manual or in the FAQ. if you do end up manually calibrating for any reason, it’ll still be subject to the allowable calibration error deviation as in the above.

it apparently does not matter if you use your phone exclusively, or if you use the receiver exclusively or if you use both. The weird part about using both (it’s not really weird… it’s a Bluetooth thing) is you have to start the sensor using the g6 receiver FIRST, and not the phone.

I don’t have the g6 but I try to stay up on the tech bc I am a geek.

good luck on your new system.


Thank you Joe. I’ve had the G4 and the G5. Did not care for the calibrating at all. I’ve been using a Libre while waiting for my new G6. I must say I have gotten spoiled to the no calibration thing. I’m hypo unaware so I need those alarms ASAP. Thank you for telling me about starting the receiver first and not the phone. That is a valuable piece of information. You are a go to Geek Guy.


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Synthia @synstokesyahoo-com, I got my notification over the weekend that I’m soon the be up-graded from G5 to G6 so I downloaded and read both the Dexcom and Tandem literature [I’ll be paring with my pump for Basal IQ and Control IQ] ; phone paring was also there. What @Joe wrote is a wonderful, concise summary of many manual pages.

An additional comment I’ll add: when unpacking and preparing your new G6 sensors, do not discard the adhesive backing! The “sensor code” to which Joe referred is printed on that backing - no other place; without that code, calibration is required every 24 hours.

Thank you Denis. I can hardly wait to get my Tandem next month. I’ve been using Medtronic for 28 of the 38 years as T1.

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I agree with what Joe and Dennis said. When I start a new sensor, I tape the code to the package top, write the date on it, and snap a pic of the whole thing. I also keep a pic of my current transmitter box. If I call Dexcom (or Tandem) with an equipment failure and they ask for serial and lot numbers, they’re with me and all in one place.

Best wishes with your G6!

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syn, since you are hypo unaware… please know that when you compress the sensor site it can cause miss readings. (its not reading the interstitial fluid) so you MUST check with a finger stick… a couple of weeks back my alarm woke me to a low of 42… and when i did the finger stick i was at 300 . know that this can happen so you don’t end up in the hospital… i think its wrong advertising on their part… yes your fingersticks are less but they still are the life line for highs or lows…

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Good to know Cynthia. That makes me rethink where I will wear the sensor. I have always used my abdomen. Maybe I should use upper arm. I have read on this forum a lot that the insertion and taking the sensor off is painful. I never even felt the g5 going in or coming out. What has been your experience?

Sometimes I feel it a little and sometimes I want to punch a hole in the wall … I’m on the g5btw. But the g6 reads the same interstitial fluid

So I’ve been using the g6 for about two months now and I love it. I have always used my abdomen for my pump until recently when I got the omnipod. I use my legs for the I’m iPod and my upper arm for the Dexcom. It just seems to work better and feel better in my arm. As far as calibrating the g6 at first I was using my pdm that comes with it, but I got tired of carrying it around so I just use it on my phone and shared it with my fiancé so when he’s not around he can see what it’s doing. The only time I calibrate is when I change my sensor after that 10th day and sometimes I don’t have too, but my endocrinologist told me to make sure every time I change it that I test my blood sugar to make sure it’s right. If it’s 20 off that’s ok but anything more you need to calibrate it and if it’s way off and you have to do it three times then you need to take it off and put a new one on and call Dexcom and let them know and they will send you a new free and it’s always overnighted to you so you have it in 2 days. They are super nice and very helpful if you have any issues.

Oh and don’t try and keep the g6 pdm on if you use your phone because that just makes it go crazy and will be irritating. I’d turn off the pdm as soon as you get it on your phone. And it’s super easy to calibrate and takes no time at all.

Thank you Lily. Lots of great tips for g6.

I have 2 kids they have been using G6 for over a year. We generally don’t calibrate, but every once in a while do it just to be safe. It is typically within about 10, but every once in a while can be further off. We manually test also if it seems WAY off, especially towards the end of 10 days or when sleeping on it weird.

No, collaboration, but yous caution , when they work most of the time its perfect, but maybe every 10 times , ir 10 weeks I have a problem with at least one of them , usually a bad sight from the get go if it’s off let’s say 50 points or more from your blood tester it’s a bad one , good luck your A1c will improve big time