Dexcom: when it works, it's great, but when it doesn't it stinks

well its my second month on my new dexcom G5. it has not been 100% out of the starting gate. i’ve had it where it is spot-on with my meter readings, and then times where i have had to calibrate it myself. then i’ve had signal losses and losses in direction arrows. some i have simply pulled off out of frustration, some i have waited it out until it got back on course.

today was the 5th day in to my sensor. i kept losing signals, arrows, signals, arrows, signals…etc. after the roller-coaster, i decided it was time to pull it off and put on a new one. well, i went through 3 others before getting one on that felt remotely comfortable. (3 of them were bleeders and had to be pulled out)

i am in the midst of a sensor warm-up session and dont know if i picked a reliable spot. i know that the first 24 hours can be a bit wonky, so i will discount that. i would love it if it worked. really love it. when it works, its like the greatest thing in the world. when it doesnt, my frustration level is matched only by a small child wanting an ice cream.

because so many of you FUD are crazy and wild over the Dexcom, i am interested in how it works for you. i have already asked about good sensor sites for accuracy and know that YDMV and to be experimental. i dont mind that. i just need a little nudge of support from the community. i know i need to have patience, but how much? how long did it take you to adjust to your sensor?

no answer is too small. all answers are encouraged. please help me to get through this; i know that when it works, its the greatest. i want to stick it out.

thanks ahead of time everyone!


Generally works great.
We used to use an ice cube to numb the area but that seemed to cause more bleeders. We stopped using the ice and my T1 just grits teeth and sucks it up now. Very few bleeders. Which my definition is the “sticky” completely soaked. A little blood that does not soak through to the outer edges is unfortunate but not a big enough deal to pull the sensor back off - for us.

We previously would get 12~13 days out of a G5 sensor - with the duration extremely reliable. For a few months now, we have been getting 6 or 7 days out of the G5 sensors. Clearly something has changed. It would be speculation to guess what that could have been.

For us, it is quite clear when the sensor is working and delivering good numbers and when it has passed its time and is no longer reliable. It is extremely unusual for the sensor to give bad number in the middle of its “good” time.

We start getting good data immediately after the two-hour warmup. Not as great as the next day, but IMHO very good data right out of the gate. I do not get concerned if the number is not spot on with the meter as I do not believe the meter even has that level of accuracy and precision in the first place. When the meter says 86 and we test again and it says 88, I do not see that as two points off. I see that as the same number.

That being said, from day #2 onwards, it is quite typical for the meter reading and the cgm reading to have less than a 10 point difference during calibration assuming straight and level cgm reading.

We have probably been using Dexcom cgm systems for about six years now.

1 Like

had 3 bleeders this afternoon, but not soaking ones. just painful ones. and, even after pulling out the sensors and pressing down on the site with alcohol wipes, about 5 hours later, the areas are still sore and discolored.

the last one i put in went in pain free and has been spot on since i first calibrated it (maybe a 2 point difference from my meter). i hope this one lasts the full 7 days worth. at least Dexcom is sending me replacements.

1 Like

What location are you using ?

I find my dexcom works best on inner thighs and back of arms. I have been getting 2+ weeks with expired sensors. Next change will be non-expired, and hope it continues to work as well.

1 Like

I’ve had a G5 for a few years. I’ve never had any bleeders.

I insert into my abdomen and while it’s uncomfortable, I wouldn’t call it painful most of the time. It seems like different bodies deposit extra fat in different places; mine ends up on my abdomen (and neck) so I put the sensor on my abdomen and that seems to work pretty well.

Sometimes I’ll get a sensor that gives me the “???” result multiple times in a week, and then go for many weeks without a single one.

I recently had a sensor that reported 80-ish, then 40-ish, then up to 100-ish or something like that.

But usually it’s pretty reliable and easy. I have lots of T1 issues, but my G5 isn’t one of them.

1 Like

What do you do with it when you’re swimming? I find when my G4 gets wet in any way, even from sweat, I get a wonky line or the ???. Nowadays I never go in the shower without covering it, even though many, many people don’t have any problems with showering.

1 Like

you’re the second person this week to report this exact problem.its odd, b/c the dexcom is guarenteed 100% waterproof. i have never had a problem with water, and my swimming has not effected the readings. i just towel dry, careful not to dislodge the sensor, and i’m on my way.

i am so sorry for your problems. i hope they can get resolved. have you called dex tech support about your issue? have they been able to help in any way? make certain that they replace the failed sensors; i have many of my own problems with the dex, and they have always replaced them Fed X overnight, no charge. i know that is not much solice for your frustrations, but at least its something.


sorry to hear about your T1 issues, whatever they may be, but happy to hear that the Dexcom works so well for you. currently, the site that i get most comfort and accuracy is on the side of my upper left thigh, close to my hip bone. i am just hoping to get a full 7 days out of my sensor. it hasnt happened for me yet :disappointed_relieved:

Sorry, I should have clarified. The jumpy line or ??? are only temporary, until things dry out or I remove the transmitter and dry underneath it. Then everything is back to normal. But it makes me careful to keep it bone-dry at all times.

not to minimize your troubles in any way, but whats the big deal with that? dry it off and move on; at least IMHO. i have plenty of dysfunctions with my dexcom. the water just doesnt happen to be one of them. i suppose that we all have our crosses to bare. UGH. maybe with a new LOT# you will not encounter this problem anymore. we can always pray. :sunny:

I can’t explain everyone’s idiosyncratic problems with their Dexcom, but mine just works. The only time it doesn’t is after 10 days it starts to go wonky and I know it’s time to change sensors.

I calibrate when it’s got a straight arrow about twice a day. I use my abdomen, as recommended and I’ve had about six bleeders in 12 years. I’ve used the Dexcom every day since a couple weeks before the STS-3 was publicly released.

I know YDMV, but my Dexcom has never been a problem.


Yeah, we pop the G5 out, use an alcohol wipe on the underside of the transmitter, let it air dry then pop it back in. Similar, when we get the ??? after a water activity. Does not happen every time but once in a while.

1 Like

I’ve finally gotten an idea that may help. As far as I can tell, you are having trouble finding good sites for the sensor because you are so lean. The tip of the sensor is supposed to be in the fat layer between the skin and the underlying muscle: that’s where the interstitial fluid is. But it sounds like in your case you have too many times where the tip goes all the way through the fat and ends up in the muscle. That would cause pain, bleeding, and inaccuracy.

Here’s the idea. If you look at the G5 inserter it guides the sensor wire in at a 45 degree angle. image

You can adjust that angle a little bit. If you were to lean the handle more upright, towards vertical, pressing the toe of the sensor in, the sensor wire would go deeper into the fat layer. I do this because it’s a technique I learned with the Medtronic guardian back in 2010 and it helped a little bit with that sensor to make it go in deeper (and I have enough of a fat layer to accommodate this.)

That’s the opposite of what you want; you need the tip to go less deep so it doesn’t go all the way through the fat layer. So maybe if you lean the handle more slanted, pressing the heel of the sensor deeper in (make sure the toe of the sensor doesn’t lift up from the skin) then the tip of the sensor wouldn’t go so deep, and maybe you wouldn’t hit the muscle. Don’t use an extreme bend here, maybe something like 5 or 10 degrees so the sensor goes in at 35-40 degrees instead of 45. The sensor wire should be able to take that much of a bend without breaking.

Just something to try in case it may help.

Do you get on the Dexcom help line before you pull the sensor so there’s no problem getting them to send a free replacement? Or do they replace it with no problem if you call them after the fact?

Sometimes I get a sore sensor — a sharp pain at insertion that continues to hurt moderately. I insert in the evening, and when this happens I just live with it and by the next morning there’s no more pain. I don’t know whether that would work in your case…


lately, b/c of all of the problems happening with the G6 coming on the market, tech support takes at minimum 1/2 hour of hold time; i just turn on the speaker phone and walk about my house doing whatever i need to do while i wait. by the time i get a rep on the line, i have already pulled the sensor out (if it is truly that uncomfortable). they have never once denied me a replacement.

thank you for this. you are the 3rd person to make this suggestion!!! i think i will give it a try next time i change out my sensor. (i am just one day in as i changed it out yesterday), and i have only had to make one calibration. generally, it is pretty darn close to my meter reading, rarely more than 20 points off, which i just overlook. sometimes it is actually spot on. i wouldnt make treatment decisions based upon it, but it has been a wonderful tool in my toolbox for management.

1 Like

I would love to try inner thighs would really be out of the way. Question? I have skinny (no way around this description) thighs. Would it work on me or fall off? Do you place up high or in the middle range? Have a little meat higher up. Also are the readings accurate? Dexcom says abdomen only. Thank you so much. My first month so am experimenting. So far only complaint is when it gives a low reading and you correct, it takes a long time to register

I heard from others that had used thighs. They suggested to put hands on lap with fingers spread a bit. Where your thumbs are is where I use, within the middle third section. (Does that make sense?)

I have a decent fleshy, fatty area there, and get good results, yours may vary.

I have heard and seen pics of folks that use lower leg/calf area, but I have not tried that location.

My readings are as accurate about the same as arm location. I use stomach for infusion sets only. Both very accurate for me.

i just changed my sensor this afternoon. i sat down in a chair and found i could pinch up some flesh on the outside of my left thigh ( i sleep on my right side and dont want compression) right between my knee and my hip. when pulling up skin, i pulled it out and away from all muscle and bone. maybe an inch or so of skin. i do not want to jinx this, b/c so far, so great. accuracy has been spot on since first calibration. (there is that little bit of lag time). and i know this b/c i have been home very sick on an elevated TB of 150%, so i have been doing finger sticks every 1/2 hour or so. so i am hyper-aware of my BGs, so i am able to really track the dexcom.

this spot is very comfortable; dont even feel it is there. didnt hurt going in either. i like this site, but am really curious about the inner thigh area. dont you rub against it in that location?

No rubbing. When I sit with legs together, I put it on the inner side, just above where my legs touch each other. As mentioned, about the same place my thumbs are with hands on lap. May be different for your body shape.

My other spot is back of upper arm. Both locations give me very good accuracy.

1 Like

Thank you! Will try on next change.

i do get some good accuracy, but it is not consistant. at least not consistant enough for me. i need to find a location that will last me more than 3 or 4 days. so, i am asking others, and i am still shopping around :wink: