G6 - TIR be damned

I’m to the point where I’m considering just saying f*ck it and no longer calibrating the G6 at all. For the first sensor it’s caused nothing but problems. Endless “come back in 15 minutes” and multiple sensors error, wait 3 hour messages.". That royally screws with loop…2am his sensor errors out and i don’t wake up and notice it until 4:15 and now it’s going on 6am and he’s still near 300.

Such an annoying system.


@ClaudnDaye, Sounds to me like a faulty sensor. I hope you changed it out and phoned Dexcom for a replacement. You should not have to put up with this kind of thing.


Harold, did you enter the code on startup? I have had much better luck with it when I do NOT enter a code.


That awful calibration loop only happens when I have blood in/on my sensor. It’s annoying but I eventually figured out that was the common thread, so when that starts to happen I know it’s a problem with the sensor and reach out to Dexcom for a replacement. Any chance that the issue for you guys?


I feel like it IS caused by me because it runs perfectly fine and never cuts out UNTIL I calibrate…as soon as I calibrate (because it’s showing an incorrect number and he’s 20% or more different up or down in his real BG), the calibration loop starts and eventually (sometimes, not always) the sensor error shows up. If I just left it alone and said “whatever” I think it would be working perfectly fine. The G5 allowed me to single and double calibrate all the time with no problems. The G6 thinks it knows best and just refuses to accept the numbers I put in.

My only reason for calibrating is to keep a good TIR, afterall, why should I / Liam have a worse TIR just because his G5 or G6 aren’t accurate and aren’t reporting his BGs correctly? When he’s truly low or high I don’t mess with it of course, but when he’s NOT low or NOT high, why should I just let it sit and linger there?

But I’m getting to the point where I’m just seriously thinking of saying screw it and skipping the calibrations to save the headaches. I’ll see if the next sensor is the same, but if it is, I will probably end up doing it and just tell the Endo - "Sorry, the TIR is what it is…if the G6 would allow me to correct it w/o spitting chunks, his TIR would be MUCH better…but it won’t, so you get what you get. I know he has only between 1 and 2% lows and severe lows and around 10% highs/very highs and the rest of the time he’s in range.

Tech is great…when it’s accurate. I’ve always used the G5 more for seeing trending data (seeing a drop so that I can correct early to avoid the lows and seeing a potential high so that I can dose more insulin to avoid severe highs)…but this headache the first sensor has caused makes me miss the G5s a lot.

We are only day 7.5 now and I probably will report it and request a replacement around day 9. I’d love to soak as much out of it as I can…I tell you it runs like a charm if I just leave it alone and never calibrate…I really think it’s me and it just doesn’t like being calibrated.

The code on the sticky paper that seals the G6 insertion gun? Yes, I entered that one and the transmitter ID. Which are you talking about not using and what’s the difference in using it, or not?

Maybe? I just feel it’s very cooincidental that it only starts happening when I calibrate it.

The G6 just thinks it knows best it seems and is standofish when you (a mere human) enter a BG that conflicts with what it sees as truth.


I never calibrate mine, so maybe that’s why I don’t have that issue. The only time I do is when it’s really off when I start up a new sensor and it’s REALLY off, but again, that’s always due to blood, for me at least. I find it to be pretty accurate when compared to my meter otherwise.


Really off meaning > 20%? That’s always the point at which I calibrate…if it’s less than 20% I don’t calibrate and let the device do what it does. For Liam, it’s just continuously off by more than 20% (mostly when it’s reading that he’s low, or high.) I followed the same practice with the G5 and it was never an issue because the G5 didn’t spit chunks when you “corrected it”

We have never calibrated a G6, even when it is off. It generally just trends back to within the tolerances within an hour or two.


The reason I ever started it at all is that, as a parent of a young one, I get to have the conversation with my Endo about my low/severe low percentages and I always used to just tell her the CGM isn’t accurate…his percentages are not as they are reflected because finger sticks show he’s either not low, or not high. So then I got sick of those conversations and just started calibrating anytime he’s showing low or high and he wasn’t really low or high (even double calibration if necessary). And that took his percentages into their CORRECT range of 1 to 2% low/severe lows. But seeing that the G6 isn’t going to allow that, I think I’m just going to go back to the previous way of doing it and just tell her the CGM just isn’t accurate when it’s showing lows/severe lows 8 times out of 10…because calibrating the G6 starts a viscious cycle.

When you first start the sensor, it asks you to enter the code. That sensor code is what does the whole “no calibration required” thing.

If you skip the code, instead you will have to calibrate twice after the warmup, and then every once-in-a-while for the remainder of the session life.

It will basically be like the way the G5 was. It no longer acts like the “no calibration required” G6. If you skip that code, it is more like the “calibrate every XX hour” G5.

Just try it and see if it works better. I like it much more.

Here are references:




That’s good to know! So, in theory at least the viscious cycle I’m experiencing can be skipped and I can go back to more of the G5 way of doing things? I always found calibrations important because, for Liam, the G5 (and G6) just have never really been accurate when it really matters (when it’s showing that he’s low or really high.)


Here is a quote from that Dexcom link:

What is a sensor code and why do I need one?

A sensor code allows you to use the Dexcom G6 CGM System without the need for fingersticks or calibrations.*

When I used the code, I found the numbers to be ridiculous. So after some trials of using the code, I went back to skipping it and just doing the calibrations.

I mean, if I am gonna test a million times anyway, why not just calibrate it?

And since I have been skipping the code, the numbers have been much better.

Keep in mind, those codes allow the sensor to give an estimate for the millions of different interstitial fluids and body types in the world. They are not specifically made for me or for Liam, they are made for millions.

Since my body does not match what their algorithm and codes are made for (which I assume is an “average” of people who use it), I think calibrations are much more accurate for me.

For people who the codes kind of match, it works fine. But I am not in that group.

If you try it, I am curious to hear what kind of results you see.


Yes! This is how I feel…at least if I am doing them and the system is ALLOWING THEM and ACCEPTING THEM, then it’s got a purpose.

I will definitely be trying it next sensor because I already know what havoc USING the code causes. I just want a similiar experience that I had with the G5…let me calibrate when I need to calibrate (to correct the CGM that is wrong) and accept it without throwing the calibrate in 15 min cycle and without throwing sensor errors.

Thanks Eric!


This pretty much matches our situation


Yes, I normally don’t check with a meter at all (except when it’s in the 2-hour warmup period), but if I just put in a new sensor and it’s reading “LOW” or under 60 or whatever and I feel just fine, I’ll check it - recently it was saying “LOW” and I checked and was in the 200s. I waited, it never went up, so after awhile I tried calibrating and it sent me into the calibration spiral. I knew what was up - removed the sensor, and lo and behold, blood.

Once in a great while I’ll check to see if it matches; it’s just not a habit since I got the G6. I usually found the G4 and G5 to match my meter pretty well too. Maybe it’s different because I’m an adult and not a growing kid? Hmm…

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We are on day 7.5 and I’m going to try and make it last as long as I can…so far in the 7.5 days, we’ve had 5 “sensor error” periods where it’s been disconnected between 1 and 3 hours and we’ve had countless calibration loops. For his next sensor, we are going to try the no-code option and see how that works out. If that doesn’t work out to be much better, we are going to try NO CALIBRATIONS AT ALL during week 3…that will give me a good idea of what to expect from each situation and we’ll make our decision on how we’ll proceed after week 3.

I’ll make sure to check for blood when we remove this sensor.


Pretty much same, I did once when it was off by like 150. I think that ended up being. a bloody sensor though. Otherwise I find it exaggerates the lows and highs but that’s just what it does.


It really is frustrating to get the Sensor Error messages and the calibration loops etc. I get it; it really is annoying and upsetting and mentally draining! That no calibration method sounds interesting - you’ll have to keep us posted how it goes :slight_smile:


I’m hoping it sets it to be much more like the G5 where you ARE able to manually calibrate once or twice and just have the numbers reset to be “correct” like the G5 would. IF omitting the sensor still results in those calibrations (once or twice) causing calibration loops and/or sensor errors, then it won’t provide much benefit. But I will definitely keep the FUD apprised of my tests on all methods used.


My doc strongly advised to never calibrate the g6

I’ve had much better performance with it since I started taking that advice