One of these things is not like the other - A discussion of CGM and Meter accuracy

I’m two weeks into G6 and that thing is pretty dang accurate. The vast majority of the time it very close if not matches my meter. G6 is also quicker to pick up movement in blood sugar than G5. I’m wearing both G5 and G6 to compare results.

So prior to G6 I would agree with you, but with moving to G6 I’m starting to believe that, for me, it is accurate enough for automated dosing decisions.

7 Likes

I’d be like PULL YOURSELF TOGETHER, kid! Feel its force! You’ve got to let it LEARN you!

I’d pay to do that. Big bucks.

5 Likes

Alli,
This story is all that AND a bag of chips!
:smiley:

Wait, you forgot the bag of chips.

7 Likes

:rofl::rofl:

Dark side or bust, @Eric. I’d get you there.

Then we’d get you a big Type 1 Diabetic t-shirt with your home address and something that says “needs insulin” in case you’re out wandering the streets after dark.

You’re not beyond help, don’t give up.

4 Likes

Please oh please be @Eric’s 670G guy. :crossed_fingers:

4 Likes

I hope he does a news story for me too!

2 Likes

Man, it is such a big a day today. As a birthday celebration, it’s time to bring the old guy back for a special presentation…

6 Likes

Oh, just what I needed. I’m gonna go show my kids again. They think I’m weird. :grin:

1 Like

OMG! @T1Allison is writing the script for next summer 's blockbuster hit - @Eric VS the Dark Side! Tickets available at all FUD locations. Order yours TODAY! Call 800.555.1234, operators standing by…

4 Likes

I’m wearing both the G6 and the Medtronic Guardian for the same reason. I’m hoping to take a little time this weekend to see the difference in how they suspend, but I did watch them through three suspends yesterday, and it confirmed what I thought to be true— in my case, the 670G just gets stuck suspending longer. Just with yesterday’s suspends, my 670G remained suspended for a total of 134 minutes versus the 75 minutes my t:slim remained suspended. This was a total amount of suspend after three separate events. I’m wearing both sensors so they were both reacting to the same information. That’s just one day, and that wasn’t even a rapidly changing blood sugar. With a rapidly changing blood sugar, my 670G would give me much less insulin. I do agree the G6 is a much more capable sensor for use in an automated delivery. It turns back on my insulin promptly, and that has made a world of difference. With that being said, I still override on a regular basis when I know something it doesn’t… which is everything. :grin:

3 Likes

So, Eric. I just have to ask what’s the full story about the photo of the two BG meters and the CGM.

My guess is that you had a rising BG, it leveled off a bit and then started running higher, so you took a nice big IV bolus and 5 minutes later your BG was around 103-105 but the CGM hadn’t picked up this sudden change because of the lag in measurements of interstitial fluid, which gave you a good opportunity to take an outrageous photo. The problem, of course, is that folks who don’t know you and don’t know better could draw a wrong conclusion from the photo depending on the true explanation behind what we’re seeing in the photo.

What’s the full story about this CGM graph climbing steadily from 50 to 167? Did it turn sharply down 15 - 30 minutes after the photo was taken? I find it hard to believe that the CGM shows your BG rising for nearly an hour, from 50 to 167, if you were just hanging out at a nice steady 103. What really happened?

1 Like

I don’t find it hard to believe at all, @bkh. I love my Dexcom… despite the fact it overshoots my actual BG on a very regular basis.

I’m confused by the question though… unless you were joking? It sounds like you actually think maybe the photo was staged?

As you probably know, I’ve also been making use of IV in order to manage my blood sugar. It takes action very fast and is unlike any other tool or type of insulin or anything I have available as a diabetic. I also snap photos all day of the discrepancies from one CGM to the next and then between them and my meters. I am, however, very careful to never post a picture that could be misleading in anyway. If I am trying to show the lag, I will state that. If I happen to catch a crappy inaccuracy, I’ll state that. I would never intentionally capture one and claim it to be another.

I also know you didn’t address this to me, but I, engaging in a good deal of what Eric uses in his own management, easily can see how he can grab such a shot without having any reason-or desire to stage it.

Eric certainly doesn’t need my rescuing. In fact, I hope he doesn’t mind my jumping in before he is able to say his piece. I’m just not sure why, as much time as he dedicates to trying to help people understand their disease and their numbers, anyone would think he would benefit from confusing people? Unless you were joking… :thinking:

3 Likes

I am not deceiving anyone like you are implying. Why would I do such a thing? I have spent two years here with nothing but the goal of trying to help others, not to deceive them.

So you want the context of what happened?

The Dexcom alarm woke me up at around 8am, beeping a high alert. I did not take ANY insulin at any time between when I went to bed and several hours after that picture.

I looked at the Dex when it woke me up, and I knew immediately that it was wrong.

I went downstairs and checked with the meters. First with my Contour, and then just for laughs, I immediately checked with the FreeStyle. The 3 readings being so disparate was comical to me. I took a pic because that is the sort of crap I see all the time, and thought it would be an interesting post.

Not only was there no IV shot involved, there was no insulin of any injection method involved for about 8 hours, other than basal.

Your accusatory tone was rude AF.

I would never try to deceive people here. I love the people here and only want to help them.

There are at least 3 people on this site who have a somewhat disparaging view of Dexcom. One of the people thinks so poorly of it, they have quit using it all together.

What do the 3 people have in common? They all test at least 20 times per day, and they have A1C’s between 4.7 and 5.3.

So you figure it out. What an amazing coincidence. Those of us who test enough to be unimpressed with the CGM are the ones with the A1C’s in that range.

Well there it is. The fact that you find it hard to believe makes it clear where the problem is.

3 Likes

Lol… and here I was thinking it was actually a relatively tight spread compared to what my meter(s) often show from my cgm. Never realized I could have been taking ‘outrageous’ photos all along

5 Likes

Peace everyone!!! There was no bad intention assumed by anyone anywhere here. What we read into a post is not always what is meant! @Eric, @bkh, please read this post before responding further on this thread:

  1. It is difficult for those who get great results from their Dexcom CGM to believe that some people may often get bad readings from them. But that is true! @Eric is one of those people who often get bad readings. There are several such people on the site. For us, 98% of the readings are within 20 (most of them are much tighter) but there are rare times when our CGM is off by 60 or so, like @Eric’s here. Despite the fact that our CGM works well for us, I could have taken that picture. So, @bkh, unfortunately for @Eric and some others this situation can be par for the course :frowning:

  2. @Eric, you have created so many funny or strange situational threads on the site! It is not surprising that someone might think, without any insult intended, that this is one of them! Remember one thread a few months ago where I sent you a PM because I was worried about where it was going! So there is no malice meant at all if someone wrongly assumes that this thread is one of them, this is the risk you run :slight_smile: Clearly @bkh assumed that that was the case, and that you would eventually explain how you had created this situation: he is not implying @Eric wants to maliciously mislead people—but, because of the narrow bandwidth nature of forums, it is easy (too easy!) to misinterpret posts. In fact @Eric, I have no doubt about your pic, but I would be interested in knowing as well if your CGM track resolved itself to a narrower error and, if so, how long it took.

  3. We have discussed at great length on FUD why some people appear to have more problems than others with CGM signals. Very clearly there is a strong correlation between lean athletes and bad CGM signals. Several of the people whose CGM signals are poor are lean athletes on the site. In fact, my son, who is lean and lanky, cannot get a sensor to last more than a week (a related issue) and, practically every time we call Dexcom for a replacement, the agent asks me if my son is lean or athletic… Diabetic athletes often have great A1cs and this might explain why some people with outstanding A1cs have poor CGM signals. Another known situation that famously leads to poor signal is poor hydration, such as a long run in a sunny day etc.

  4. There are also tons of people, the very large majority of them, for whom such discrepancy as shown on @Eric’s never or hardly ever happens! So this is not something that should be feared to happen often—and when it does, for the average person it does not last long. Don’t let this put you off from using a CGM: CGM are amazing tools that save lives and improve A1c.

  5. Above all, everyone pls remember that IT IS EASY TO MISREAD SOMEONE’S INTENTIONS ON A FORUM. If you are unsure, or feel that someone’s post is disrespectful, personal, or misplaced, please involve a moderator or PM the person nicely to let them know that you feel there may be a problem in their post.

Now peace! There was no disrespect intended by anyone :slight_smile:

10 Likes

Sounds very similar to my day about half a week ago.

Me being more private than others, discussed in in PM instead of publicly.

7 Likes

Some of us are just more drawn to public displays and sharing of … well, everything.

Then there’s the next level down, like Eric, who just wants to share his diabetes stuff. :grin:

We might get you there yet… get you doing some selfies… :grin:

6 Likes

ha ha ha
Now that has me almost falling out of my chair LMAO.

4 Likes

If you can get @Thomas taking selfies…let alone sharing them…I’ll have to conclude that you have superpowers beyond what I was already aware of.

6 Likes

I had to read it twice to make sure it was applied to you :smile: