# One of these things is not like the other - A discussion of CGM and Meter accuracy **URL:** \ **Category:** C/GM\ **Created:** [February 13, 2019, 4:17pm UTC](https://forum.fudiabetes.org/t/one-of-these-things-is-not-like-the-other-a-discussion-of-cgm-and-meter-accuracy/6577 "2019-02-13T16:17:34Z")\ **Posts on this page:** 1\ **Showing post:** 51
**Author:** ![Eric](https://yyz2.discourse-cdn.com/flex030/user_avatar/forum.fudiabetes.org/eric/32/9209_2.png) [@Eric](https://forum.fudiabetes.org/u/Eric)\ **Post date:** [February 15, 2019, 5:33am UTC](https://forum.fudiabetes.org/t/one-of-these-things-is-not-like-the-other-a-discussion-of-cgm-and-meter-accuracy/6577/51 "2019-02-15T05:33:00Z")
> [@bkh](#): > > 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. 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. > [@bkh](#): > > So, Eric. I just have to ask what’s the full story about the photo of the two BG meters and the CGM. 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. > [@bkh](#): > > 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? 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. > [@bkh](#): > > 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. Well there it is. The fact that you find it hard to believe makes it clear where the problem is. --- _[View the full topic](https://forum.fudiabetes.org/t/one-of-these-things-is-not-like-the-other-a-discussion-of-cgm-and-meter-accuracy/6577)._