Dexcom always reads high for days after starting

Hi All,

I've lurked for a while, but just joined up, mainly because I have noticed an irritating trend with my Dexcom.

I've had the Dexcom for about a year now, and it's generally been good. I always insert in the morning (always in my belly), and try to keep my sugars stable during the startup period. I only calibrate when sugars are stable, and never in the morning (to give it time to normalize after I've rolled around on it all night :-) I almost always do 2 finger sticks to make sure my meter reading is accurate before inputing a cal value into the dexcom. The only thing I do that is a little sketchy is that I am often in meetings when the initial cal period ends, so I sometimes wait to input the initial two readings for up to 2 hours after the unit starts buzzing.

The problem is that a new sensor always runs high for the first 3 or 4 days of the cycle. This particular one took 5 days... Every time I calibrate it's running high.

After 3 or 4 days, it is generally accurate, and if I restart it continues to be accurate into week 2, so it seems to be something specific to the sensor rather than the computer. This is anecdotal, though, since I rarely re-start, usually I just pull it at day 7 and start a new one a day or two later.

Anyone else notice this? Perhaps there's some known fix for it?

Thanks in advance!

If you would wear the sensor until it failed you would see the signal get stronger and then after some length of time you would start seeing it drop giving false lows. This is normal for the currant technology, try doing a cal every 6 or 8 hours for the first few days...It appears that your sensors take a long time to get wet.

I haven't run into this problem but I can say that waiting to input your 2 cals isn't hurting it.

Thanks John,

When you say "get wet", this is the sensor acclimating to my skin/tissue? Are there any general guideline on what people have seen with the duration of this process? Perhaps there is some effect from my diet (too much salt slows it down or something), or other medications?

Next sensor, I will try checking cal every 4-6 hours, and keep a log, see if it goes out of sync only at night, or as a more gradual constant divergence.


Thanks Don, good to know!