Hey folks, I've been using my Dexcom G4 for all of about 24 hours. I'm really liking it so far. I do have one question, though... actually two. The first is, this morning I entered a blood sugar for calibration. I'd been flat all night. The receiver was reading 126. I put in 129. Then the receiver said 139. This also happened last night, when I entered a BG that was slightly higher (but not much) than what the receiver was registering, but after calibration, it overshot what I'd entered by 10-15 points. Any clue as to why this would be?
Also, I've got some Tegaderm on my sensor (because it started coming off when I worked out yesterday) and I was just wondering - will I have to change the Tegaderm if I try to use the sensor for a couple weeks?
Thanks in advance!
I use to use IV3000 tape and I would have to replace it every few days. I found something called skintac that you put on before you install the sensor and my 7 plus sensors stay on for 14 days no problem. Its a liquid barrier that sets up on your skin before you adhere your sensor. Just leave a small spot for the sensor to go through bare. Skintac if it comes in contact with the prob will mess up the sensor. Good luck!
I use skintac as well, works well, no need to typing over.
Regarding calibrations, no worries there. Keep in mind that your blood glucose meter is not super accurate as well, so when you calibrate sensor will not go automatically to the number you put in but it will just take in and process. You will see that it tends to be more accurate after few days.
Regarding using it for another cycle, my record is 21 days, but some sensors go bad after 7-8 days and there is no way to get more from them.
good luck and enjoy
I have been using the dex 4 since january and I find the same thing happens to me on occassion. I have no idea why, but you are not alone in this type of experience. Just remember the dex is less accurate then the meter
I have been on the G4 for a little over a month. I had the same issue on the calibration. I would have it go higher or lower than either of the numbers at times. I called their support to ask if it was broken or not.
They basically said that 1) it isn't to be used for taking insulin, 2) it is an advanced logarithm that calculates where it should go and/or (this one sounds more logical) 3) the sensor has already been sensing and it is predicting where it will be shortly as it calibrates. But with me, most of the time there is a strange shift as you say, regardless they act like it is no big deal so I don't worry about it.
I, like others here, use Skin-Tac successfully along with IV Prep Wipes. I use the IV Preps to stick it, since it can go through it and not fail (for me) and then about a week later it starts to come loose around the edges and I apply the Skin-Tac wherever loose and get another week or so out of it. I have used two so far, not counting the one I used straight Skin-Tac even where the sensor goes...and it did not sense very well.
Good luck and I started a post when I went new on G4 you may want to check out, lots of good stuff for us noobies.
CGMs use algorithms to calculate the blood sugar based on the most recent measurement it has taken, all previous measurements, and any calibrations you enter. These kinds of mathematical algorithms are very complex, and it is not bad that it doesn't match the most recent calibration. Your fingerstick meter has inaccuracies also which are (probably) taken into account in the CGM calculation as well.
I have spoken quite extensively with Dexcom about the G4 and calibrations. The algorithm used in the G4 is supposed to be much more resilient when it comes to entering multiple calibrations - apparently older models could easily get out of whack if you entered too many calibration values. These are the rules we use for my daughter based on these discussions with Dexcom:
- Always enter a BG at wakeup and at bedtime. If things are going smoothly, these are the only calibrations that should be needed.
- Calibration BGs should be entered approximately every 12 hours or when it asks for them OR at wakeup and at bedtime. You can and should preempt when you know one is coming. For example, if I enter a BG into the Dexcom at 9am, I will enter one at 8pm (bedtime) even though it hasn't asked for one yet.
- You can and should enter additional BGs into the Dexcom if and only if the finger poke BG is more than 20% off from what the Dexcom reads. For example, if Dexcom reads 300 and finger poke reads 260, that's fine. If the finger poke reads 230 with Dexcom still at 300, that's more than 20% off, so enter that value into the Dexcom.
Hope this helps.
How many times a day do you calibrate G4? Of course at least every 12 hours. But I used to use MM cgm and found that needed much more calibration.
