Just started a new Dexcom G6 sensor yesterday and had crazy low numbers on it. It woke me with a 44 with a straight down arrow. I tested and was actually 100, but it scared the crap out of me. How long do your new sensors act crazy? Or do they start out accurate from the beginning? When is the best time to start a new one, so you can keep an eye on it?
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How fast did the graph show the 44 and did it recover by itself within a relatively short time frame?
Was this a compression low ?
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@Thomas Don’t think it was a compression low, the sensor is on my left arm and I sleep on my right side. I started getting data from the new sensor about 5:30 pm, went to bed at 10 pm and got the 44 down arrow at 11 pm. Calibrated it to 96, and got another low of 67 at about midnight. Calibrated it to 101 but had already eaten a graham cracker and cheese, and spent the rest of the night above 200 (via Dexcom and fs). 
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Most of our G6 sensors are good but for these potential reasons and because we use the data to drive Basal-IQ, I very much prefer NOT to start a sensor at night.
When we do then I set alarms and check w/ meter to verify the new sensor a few times during the night.
I expect ballpark accuracy by 2 hours after warm-up has completed. I expect excellent accuracy from our Dexcom G6 by 12 hours after warm-up has completed.
On a sensor restart, it is typical that I would have to put a couple calibrations in during the first 24 hours and maybe 1 or 2 more in the next 24 hrs. On a new physical sensor, having to calibrate means (for us) that something is wrong.
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With the first 24 hours of a new sensor I’ll finger check to make sure it’s reading alright. After about 24 hours they tend to be more accurate for me. If I think ahead enough, sometimes I’ll insert my new sensor while I still have the old one up and running. That can give it some time to marinate, let the initial microswelling to go down and more accurate readings for when I switch over to that new sensor.
If the new sensor is wildly off even after some calibrations then I’ll pull it out and contact Dexcom for a replacement. This has only happened once or twice since using the system for 10 months
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You may consider just calling the company to get a replacement sensor. This is greater than 20% variability that they honor. They mentioned staying hydrated since the sensor uses interstitial fluid to measure the BG. I still don’t like this “0 finger sticks” that they advertise. My CDE told me checking is still the gold standard.
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Unfortunately with the G6 this has changed to 30%.
(Which is not to say the OP was or was not within a certain percentage. lol.)
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For me, too, the first 24 hours is often off. I will do a finger test and if it is off 30+% (usually) I will calibrate. I usually calibrate 2-3 times first 24 hours. Then it seems to take. My sensors never last more than 10 days, and often less. Generally, noise starts appearing on day 8 or 9. I usually leave it though if it is not too off, because I’m tired of calling Dexcom and explaining time and time again. By day 10, I’m happy just to replace it and start all over again with a fresh one.
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although I am on the FSL and not the Dexcom, I experience similar patterns the first 24 hours. it settles down but by the second week (they last 14 days per sensor and cannot be rebooted) they are dead on accurate with an infrequent 15 minute lag time if I am not flat.
I also have the hydration issue; the more I hydrate, the more accurate my readings are compared to the finger stick.
also, like with Dexcom, Abbott will replace any sensor that is problematic (in any way). Ive even called their tech support bc my new sensor hurt when I put it in.
Oh yes. I remember that now. Seems like the accuracy should have went from 20% (g5) to 10% (g6) or some improvement. I hope the g7 accuracy improves. Thanks for sharing the information.
24 hours with an accuracy of about +/-8 hours.
This is why when my sensor starts failing after the first restart (at 9 days) I put up with sensor errors; they cure, initially, after under one hour. Somehow the transmitter is handling a failing sensor and correcting the readings. That seems like a major technological achievement to me because with the sensors I’ve encountered in the past when they started to go wrong you just got a new one.
Anyway, the first failures typically happen within a 10-14 day range (so after the restart).
My algorithm for replacement is then driven by that 24 hour warm up period; I really don’t want to go through that, but if the thing is dropping out for an hour every six hours I replace. I don’t do this scientifically, it is all emotional; when the sensor fails make me feel I can put up with the 24 hour warm up I replace.
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