Dexcom and?

I know that a ??? message on the Dexcom means that Dexcom cannot make sense out of your blood glucose readings. After a steep spike, which started at 1:30am, Dex alarted at 1:50 am, in which she climbed 100 points, I was fighting highs all night. She is 12, growth hormone related, I’m sure. I used aggressive corrections, even overriding pump plus a 200 percent temp basal. Changed site and insulin at 3:30 a.m and she started coming down at 5am. I don’t think this is due to a failed site, however, as this happens maybe one week out of the month. Sometime when her BS was 278, Dex reading higher in the 300s, Dex lost track. I had ??? until 7 am. I put the Dex receiver in a pump pack to be closer to her sensor. What do you do with ??? How long should you wait to ride it out? P.S. Dexcom DID come back into range eventually.

The simplest advice I got was to shut down the Dex and restart it. That works very much of the time for me.

We change basals about three times a week. The times of highs are always within the 6pm thru 2am period, 95 percent of the time. This has been going on at least a year and a half and she was premenstral. May be cycling nonetheless, but it is for the most part growth hormone related, I think. We have to change basals so often that we don’t bother setting up rates; just change the one basal. While her pattern remains somewhat stable, the amount of insulin differs. It’s not like you can have a “high” setting. During one “high” period, she may use anywhere from 1.9 to as much as 2.7 per hour for short periods and then crash.

Dexy is not very accurate in the highs above 200+ the best thing is to do a real blood test to see whats really going on

The Dexy Seven Plus is accurate up to about 300 if not slightly higher!
I’ve done blood tests of 289 and my Dexy is reading 282 which is nearly spot on.

It is more about the way a CGMS measures your blood sugars, through the interstitial fluid under the skin and the 10-minute time delay it takes for the blood sugars to sweeten the interstitial fluid. If your sugars are rising or falling when you do a blood test, you CGMS will always be out by quite a bit, but if they have been steady for longer than 10-mins, then you should find it to be quite accurate.

Youv’e also got to remember that blood test sticks have a 31-point tollerance! This means that if you did two blood tests at the same time, both results could be 31-points apart and both are still accurate. I see this each time I start a new sensor and my Dexy asks for two blood tests.