Sensor lows at tail end of sensor life

Like many dexcom users I always try to get more than one week out of a sensor. Typicaly I can get 10-14 days. It’s interesting to me that the place I most notice deterioration in accuracy is at the low end of the BG scale. During the first week there is rarely a problem but towards the end of week 2 my sensor has a harder time telling what is or is not a low reading. Instead of getting ??? as the sign that it’s time to change sensors, I simply experience sensor readings that are 20-30 points below my BG readings inspite of recalibrations or restarts. I’m curious to know if others experience this problem. It seems to be exacerbated at night when the restarted sensor will often go to the lowest BG level on the Dex even when I’m in the 80-90 range. For me it’s turning out to be Dexcom’s “official” one week period that is the most accurate, with problems normally starting after day 10-12. I’m a big Dexcom fan and don’t mean this as a criticism of the device - especially since I’m pushing it beyond it’s stated tolerances.

I was originally going to say I hadn’t had this happen at all. (For the sensors that work, I’ve always gotten at least 20+ days of accurate readings. My problem is that it will start telling me at around 25 days that I’m going up and down (giving my a rollercoaster) even when I’m holding perfectly steady.)

I am trying to think about whether I have this problem. I don’t think I do, but I will pay more attention next time it tells me I’m LOW. But maybe it just varies by person and does different inaccurate things depending on your body?

I typically get 10-12 days on a sensor with the most accurate days being 7-10. I have not had the same situation as Mike described, but toward the end of a sensor’s useful life and before i gt the ??? the sensor sometimes becomes unresponsive and simply stays steady. Allen

Thanks for your replies. I guess everyone’s chemistry is a bit different which explains why a given sensor’s demise occurs in different ways for all of us. The Dex is a great tool and I expect it will only get better with Gen 4. Mike.

Mine is the opposite, it will accurately read my lows but totally miss the highs. And the changes are slower - none of the single or double arrows either up or down.

Fascinating - just confirms how unique we all are! Thanks.

I get the low readings too which indicate the sensor needs changing as I can no longer trust the readings are accurate. When the low readings keep waking me up at night when I am actually 7 is so annoying and I use more test strips to check my actual readings than I would usually use. Another indicator that I need to change sensor is repeated ???, I have not had sensor failed just these signs, and once I can no longer trust the readings then it is not worth using it.

Anna (another one!!)