I just called Dexcom for inaccurate readings. I’ve been having them all day for 10+ hours (some off by 80+ mg/dL!) and finally decided to call them. They will send out a replacement since I still have 4 days left on this bad sensor. The Dex rep said typical reasons for inaccurate readings are i) dehydration, ii) loose sensor, moves around, iii) insufficient fat where inserted, iv) laying on top of it causing compression low. So only possibility for me would be (i) or (iii), though the sensor was pretty accurate 'til today.
I also asked about pre-soaking. She said that the G6 should be accurate after the 2 hour warmup without pre-soaking. If not, calibrate it but if it continues to still be inaccurate after 3 hours then it probably means the sensor is bad. Also, do not over calibrate. Too many calibrations can cause it to be inaccurate.
The Dex rep also recommended that you wait 10-20 minutes before starting the new sensor after removing the old one, i.e., before tapping “Start Sensor” after inserting the transmitter. I never wait that long but will when I change this bad sensor and hope that improves its accuracy.
To submit a sensor issue (to get a sensor replacement) without calling fill out this form.