I have be using the G4 system for about 8 months and I figure about 1 in 5 (20%) of my sensors don't function properly and have to be replaced before the first week is up. Having using Dexcom CGM's for over 3 years I gotten very consistent about applying new sensors and the ones that have problems usually occur in the first day or two. Luckily Dexcom is very good about replacing the early failure sensors, which leads me to believe that my experience is pretty typical and is why they are so good about doing it, but I would like to know for sure by asking other users on there early failure rate to see if that is true (I'm sure Dexcom won't tell me)?
I have to say that mine also have failed a few times, which was unusual for me in general. Could you post your reference and lot of numbers so that maybe we can check and see whether those are similar batches. The expiration date would also be an interesting thing to know.
I've been using their G4 system for a year and a half, and before that their 7+ for a year (I don't what a Dexcom "3" is...). Almost none of my sensors go bad. I could count the number of bad sensors I have had on one hand (and even if I were missing a finger). Seriously, I think I have only had four sensor go bad on me (that I can remember). In any case, it is few enough so that I don't even think about it.
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I'm a newbie here time wise and have only been using the G4 for 6 months. I have not had any failures that were not related to sensor movement. Either from too tight clothing over the sensor location or a location that got banged/knocked loose during daily activities.
I have used the G4 for over a year and I too could count the number of sensor failures on 1 hand - minus a couple of fingers.
I had three replaced in the last three months and actually asked the dex tech person if this was unusual (I didn't have that many replaced in the first 9 months of using it) and she said it wasn't uncommon and it wasn't an excessive amount of replacing. Not sure if what tech support said was true, but if it is then it would be about your failure rate. As long as they replace them I am happy.
I do have to say that if a sensor works well in the first couple of days they are usually good for a week+.
Dexcom is very good about replacing bum sensors, which leads me to believe that despite the fact that they are definitely more accurate than the Seven Plus, problems are still common.
My failure rate has averaged about 1 out of every 6 or 7 sensors.
I’ve noticed that accuracy can be WAY off in the first seven days. If you can stick it out, it gets much better-at least it has for me-after that.
I'm new to Dexcom, and currently on only my 4th sensor. So far I've been getting a good 4 weeks out of the sensors, so I'm very pleased. However, this current sensor I am using I've got some concern over. The first 3 seems very accurate in my expectations. The daily 2 regular BG tests I'd do to calibrate would usually be within a very small variance from what the Dexcom would currently show. Usually under 5% difference at most, sometimes dead on. But this 4th sensor is usually around 20% off so it seems to be having a lot of problems. I've only worn them so far on my abs, so nothing changed in location that might affect it. Do you folks see this kind of issue at times too?
What's the reference (REF) and lot of numbers? What's the expiration on it?
The problems seems to have no correlation with how close they are to the expiration date. I usually get 3 boxes with 4 sensor in a box at a time, most are from the same lot. I have gone through two orders like this and I have gotten about 6 replacement sensors (some of those also failed), so all told I've had 30 sensors and 6 of them have had early failures, hence the 20% failure rate. I do think there is a weak correlation to failures within a lot however Dexcom Tech Support tells me that each sensor is individually made so that tends to backup my statement that failures are random but there probably is some correlation to certain lots having more failures.
Random events would be same in other users' experience. If you are right about no correlation with the lots, it would mean you personal handling may have something to do with the failures. Have you analyzed your insertion, activity, etc.?
I do see same thing with some sensors - just like your experience. It seems random as I analyzed my insertion and record what and how I manage it, which did not reveal any particular practice that would associate with inaccuracy.
I am impressed with your sensor longevity. What exactly is your practice (insertion, care, etc.) that allows for such long use out of each sensor - 4 weeks!
I am curious, too, 4 weeks is incredible! I'm jealous ;)
I've probably used 16 sensors of the 24 sensors I've ordered plus 6 replacements or 22 total, in 8 months (32 weeks). Considering I lost a week for the 6 bad ones that means on average get a little over a week on a good sensor but the average seems more like 2 weeks and the longest one lasted was 3 weeks. Reading the posts I think this is typical.
I put the sensors on my upper buttocks bulge (nice meaty place)closer to my hip, just below my underwear line. I gets about the same life as Dexcom recommended abdomen site but I love that it is it covered and protected by my underwear and is always out of site. I also use Skinprep before applying and Flexifix to tape around the edges. I've had a couple sensors go 3 weeks without any problems with adhesion.
I had the old Dexcom system. Never had any issues. Switched to the G4 and I am in the same boat as you I could not get through the 2 hour calibration time. And a failed sensor. Not sure why this particular batch is doing that. With that being said Dexcom says it is so so common and they are great about replacing them. Once I get throughout the two hour calibration time I am good. I just had some battery issues so it is being replaced. Still waiting for the system. My insurance does not me allow to get my stuff from Dexcom direct. I have to get it from edge park and it is not been such a good experience for that. Reordering supplies has been good. Not this. Two day express should of been yesterday. Now it is the 13th. This machine is my life line. Not important to them. Anyway you are not alone with changing the sensor. Good luck
Have you tried letting a new sensor acclimate for 8 to 12 hours rather than just the 2 hours start sensor time. I have tried just 2 hours and only about half the time are the readings well behaved from the start but if I wait the longer time they are almost always consistent from the start unless it is a bad sensor. I've heard this from several other people and I also found this true.
I'm still too quite new to Dexcom. Started in end of October and running my third sensor at the moment. Started fourth week with it again...
(Have only used my upper arms)
But when you say they fail, how does that occur? Do you mean that the sensor does not start working or is the accuracy very bad all the time?
The readings are off or don't track, or too frequent question marks or don't go away within 3 hours (Dexcom recommends if the ??? don't disappear after 3 hours you should replace a sensor). I have tried to restart a sensor but rarely does that improve things.
I've been using Dexcom for 7 months and only had one sensor go 'bad" within the first week. I had one that seemed "off" -- but it was the transmitter that was bad, not the sensor - they replaced the transmitter under warranty and I was fine.