Dexcom G6

[diabeticjohn]

Hi All,

I posted in the newbies thread the other week about (finally) starting to get serious about my Type 2. I bought the Dexcom G6 and started using it last Wednesday. The first day the results were awful, but got better as the days passed. I got drunk on Saturday which caused my phone to go crazy with beeps and bells telling me that my mmol/L was too high and I was a terrible person (ok maybe I just thought that).

Last night around 2am it started beeping saying my mmol/L was 3.8 and in 20 mins would be 3.1 if no action was taken. I've never been in a situation that my mmol/L was anything other than too high. So I got up, and I thought I'd check it with my meter. That gave me a reading of 5.6... What I'm wondering now is the accuracy of either of them as I also noticed that my meter strips were now out of date.

I've had a wee read on the Dexcom FAQ's but that seemed to confuse things further by saying it measures different things and there's no need to calibrate, unless you need to calibrate?!

I'm kinda disappointed because I felt like I was doing really well and for the most part my readings were that of a non diabetic, and now I feel like it was all a lie...lol...

If anyone has some real world advice on this that would be wonderful.

Cheers....

John

 

[Sally71]

Could you have been lying on the sensor while you were asleep? That can make it read low when you aren’t.

 

[Pumper_Sue]

G6 is not very accurate for first 24/48 hours and also has a hissy fit regarding accuracy when either to high or low. That's my experience anyway.

I would never ever trust it to make a clinical decision.

 

[rebrascora]

I don't have experience of the Dexcom, but I have Freestyle Libre and it reads lower at low levels than a finger prick. It may be as much as a whole mmol unit at hypo level ie below 4. I think they are set up that way to ensure people on insulin are kept safer.
What I would say is that it is perfectly possible for a non-diabetic person to drop below 4 during their sleep and it not be a concern, particularly if you had done quite a bit of exercise or activity the previous day or even possibly a delayed impact of the alcohol from the previous drinking session. Alcohol can have opposing effects on BG levels both high and low (depending on your tipple) and can be unpredictable, especially if a larger quantity is consumed.

These sensors are primarily designed to keep insulin users safe but as with everything, including your BG meter, there is a margin of error, so neither reading is guaranteed to be correct, just to give you some guidance but in general we would be more confident of a finger prick BG reading than a sensor as they have an algorithm build into them to make some adjustment for anomalies.

We often tell newbies not to get fixated on any individual reading and look at trends rather than any particular BG value because the overall trends will show a truer indication of what is happening than any one or pre and post prandial pair of readings. So many factors affect BG levels that anomalies will occur bucking the trend and you just have to accept that.

You might be best setting your low level alarm higher to avoid rude awakenings like that again, since you are not on insulin or gliclazide and therefore not at risk of going too low or just cancel the low level alarm if that is an option.

****Edited to add.... that should have read..... "You might be best setting your low level alarm lower", not "higher" ****
Not sure where my brain was when I typed the original message.

 

[diabeticjohn]

Thanks for all your replies guys, really appreciate that. I think I have become rather obsessive about the actual numbers, but it's really good to see, for the most part, a relatively straight line since I've cut out almost all sugar/carbs. From the comments above and other advice I've been reading on the forum trying to make sure that the changes from fasting to 2 hours after eating aren't too dramatic, is that a fair statement?

@rebrascora one of the reasons that I started to be more sensible around this is because I was prescribed gliclazide as well as the 4x500mg Metformin and the Empagliflozin that I was already taking. So, for the moment I've decided not to start the Gliclazide and see if I can avoid adding to my medication.

I was going to speak to the diabetic nurse about this before I did it, but she's on holiday at the moment and so I figured that if I have a couple of weeks of data showing where I'm at and she still thinks I should take it then I'll start it.

Again, many thanks to everyone for their comments.

 

[Thebearcametoo]

One thing we’ve found with the dexcom is that if there’s not enough fluid because my daughter’s been lying in one position for too long that it’s not getting enough to take a good reading or her fluid levels are low then a bit of a jiggle around and some water can bring you up and stop the alarms. For my daughter I can guess when it’s this fluid issue by seeing the extent of the drop. If she goes down slowly it’s an actual hypo whereas if it drops off a cliff it may well be this fluid issue. Annoying when you get woken up for no good reason (like last night) but if doesn’t happen very often. (Obviously this may be different for you if you’re not using insulin but thought I would share our experience for more info)

Tech is a good support for getting more information about your diabetes but it is fallible. Try not to get too bogged down in any of the details but use it to help you see patterns.

 

[everydayupsanddowns]

Yes I would suspect a ‘compression low’ too for that overnight

I have all but given up feeling the need to cross-check with fingersticks during the daytime, because the G6 has tracked my BG as measured by the Contour Next XT so well. The current sensor I am wearing is probably the wobbliest, but it is still well within usable limits, and occasional calibrations where BG is level have pulled it back into line.

Having used a few different brands of sensors over the years, they are all a bit ‘laggy’ when BG is changing rapidly, and some have algorithms that try try to close the ~10min gap between interstitial glucose and capillary blood glucose which can give the impression of overshoot when rising or falling rapidly. It is also pretty clear to me that different sensors work well for different people, and that each individual needs to develop a sort of intuition about how the sensor acts and reacts for them.

If you can do that, you’ll generally know when you can ‘trust’ the sensor reading, and when it is wise to cross check with a BG meter - which will be slightly different for each person I think 🙂

 

[m1dnc]

Totally agree with Mike about different sensor systems working more or less well with different people. For me, I have found the G6 to be very reliable, but I know some have found otherwise. I too have tried several different systems over the years (does anyone remember the Glucowatch from the 90's?), and I have found the G6 to be the best.