I’ve been on the G4 for 6 months, and for nearly the entire time, every morning after breakfast the G4 says I’m anywhere from say 80-110, but when I do a fingerstick, that result is much higher like 160-180 which is well outside of the range the Dexcom is supposed to off by. So I always re-calibrate since it has a steady arrow during all of this anyway. It doesn’t seem to be a matter of it “catching up” because it never seems to recognize the morning rise at all which is perplexing.
Anyone else have this issue? Any idea why this is happening or what to do?
The dex has some quirks that you will need to think about in relation to your readings.
If the sensor is in a place that you roll over and lay on over night then you will run lower than what a FS will show. It compresses the tissue the sensor is in and does not allow the fluids to refresh the reading.
The same thing will happen when you are dry - as in a bit on the dehydrated side. Put laying on your sensor and not drinking a lot before bed and you've a combo that will trick your reading. If you know this is happening you can try alternate sites. and you can always take a glass of water at bed time and one when you get up in the morning.
You are supposed to check with a FS BG before you treat with either food or insulin to be safe.
Eventually you will understand what your patterns are and adjust accordingly. For me it took moving it to the back of my upper arm that I do not lay on, and a large glass of water in the hour or so before bed. If I get up to empty out at 3 I will check it to compare, and if it pinks me low in the middle of the night I will always check before eating. I can actually see the ups and downs as i roll over in the middle of the night.
I always check with a finger stick before treating with food or insulin -that's how I know the sensor is full of crap--haha
That's intersting for sure about sleeping on it and rolling on it--how annoying becuase I always have it on my abdomen or love handle area, so it's hard not to lay on it or roll on it, but I guess that makes sense about maybe the tissue being compressed and the fluids not refreshing the reading, but the reading is still low even after I've been awake for an hour...I wonder why it doesn't correct during that hour that it's no longer being layed on. I guess I will try to drink more water before bed and right after I get up to see if that helps.
Yes this is exactly my understanding of how it works. The BG reading is coming from the interstitial (sp?) fluid, not one's blood. With lack of movement, or compression, the glucose in that portion of interstitial fluid in which the sensor is sitting, can become depleted of glucose - thus the false lower reading. Back of the arm sensor placement and hydration have been the keys for me too. If I'm going to wear it on my abdomen I try not to sleep on that side. Good luck!
Very good points...thanks Mike!