Wearing a CGM Sensor Longer than "Recommended"
Continuous glucose monitoring systems have improved a lot over the past few years. I love my G4 from Dexcom and feel it’s a greatly enhanced over the other CGMs I used back in 2008 - 2010. One of the improvements is the approved duration of sensor site life. The G4 is FDA approved to be worn for 7 days as opposed to the last CGM I used which only had a 3 day lifespan (per the FDA).
Word on the street (or the virtual online/blog street) is that sensor sites can last much longer than 7 days with only incremental changes in accuracy. Another Dexcom user told me recently that the longest he had worn the same sensor was 27 days So, I used that as a benchmark and tried to see how long I could keep my last sensor on and working.
The site was on my lower right hip and it worked very well and was painless for almost 3 weeks. Then, I started having some triple question mark symbols ("???") - typically at night when the Dexcom receiver was under my pillow. The accuracy wasn’t as good as the first couple weeks, but generally pretty reliable. Another thing I noticed was that the trend arrows would often disappear, even though the blood sugar value was still showing on the screen and fairly accurate.
Around the 22 day mark, the site started to fee sore, but only if I pushed on it. Also, the skin around the adhesive was starting to itch a bit. Finally, at day 26 I decided to pull the site out. The skin under the sensor adhesive was a little read and scaly. It really itched too! But, it calmed down quickly and is healing fine.
When I started the new sensor site, I found that the accuracy was really great! I kept testing my blood and getting the same result as the Dexcom currently displayed. Maybe I had gotten used to it being a little less accurate?
Although I’m sure it’s not recommended, I like the fact that these sensor can last this long. Maybe I won’t routinely wear them past the 3 week mark since accuracy and comfort are obviously important. But, stretching the diabetes maintenance dollar by wearing a site longer sure is nice.
Anyone have any advice or words of wisdom about CGM sensors? How often do you change your sites?
Kelsey wrote for HealthCentral as a patient expert for Diabetes.