Crazy highs and lows

Hi everybody -

So - over the weekend, my Seven Plus was giving me crazy readings - lots of highs and lows; I thought I was doing a terrible job of controlling my BG for some reason. But I noticed that my fingerstick readings were getting farther and farther from what my Dexcom was saying - by last night, I read a 118 from my regular meter, and a 220 from my Dexcom… and just an hour before it had reported a false low. So I junked the sensor and inserted a new one this morning. I’ll see how it goes, but has anyone else had this happen? And was it a bad sensor or a problem with the Dexcom unit itself? Thanks, Tony

How old was the sensor, Tony? I have this kind of behaviour only when the sensor is about to give up, which lately has been in the middle of week number 3, not too bad…

Also, did you take a shower or went to pool during the weekend? I have noticed that sometimes water or moisture can influence the readings.

Last thing, if the sensor is not too old, you might stop it, then start it again so the machine thinks it’s got a new one, and will recalibrate it. This worked me a couple of times after getting a lot of ??? on a fairly new sensor.

Ciao, Luca

My question would be. Did you calibrate the dexcom. I would have calibrated it with the 100 point difference. I actually find a lot of times just a general restart when it is off and can’t find it’s way works to fix the problem.

It was pretty new - 3 days - but I was on board a boat in the middle of a tropical storm (interesting time). I certainly got wet on the outside, but my foulies kept me pretty dry… maybe it was more the general dampness of the situation. I calibrated it for sure - maybe too much. Hmm. Well we’ll see how this new one does. It was weird - and a little unnerving, as I’ve grown quite fond of my Dexcom, and feel a little naked without it now.

Yeah, did the mistake of overcalibrating once too, but I was at the end of week 2 and so I decided to change sensor anyway.

It’s definitely best to follow the advice of the box, and only insert a reading when asked to.

Have you tried to get in touch with Dexcom to get a replacement sensor? I’ve seen many other messages here, and they were all happy of Dexcom’s support, they all got a fresh sensor mailed to them at no charge. Worth a try!

Ciao, Luca

I hadn’t heard that it’s best just to calibrate when it asks for a reading. I’d been told the more readings from a meter you enter, the better. Tell me more about what you know.


this document published by Dexcom might shed a little more light for you:

This is what I was referring to:

“Calibrate when the Receiver asks you to or a minimum of once every 12 hours”

So, entering too many readings might actually confuse the calibration in the Dexcom, and should be avoided. There will always be some error due to the different way of measuring BG, and we should always remember about this.

Ciao, Luca