My first sensor lasted 7 days, but accidentally tore it out because of poor adhesion. My second sensor is on my arm and has been doing pretty good staying put - I even put extra tape on it and it’s solid as a rock. I just finished my 7 days and decided to restart the sensor to see how accurate it is. I’ve heard several people that you can get much more time out of a sensor.
SO far since restarting my levels have been fairly accurate. Last night (9pm) I was buzzed for a low at 79 - meter said 88. Not bad. However I got the dreaded ??? at from about 3-5am, but went away shortly after I woke up at 5. If you have followed previous threads you will remember I had the ??? a lot at night after inserting in my arm, and this is first time I have seen them since then. When the ??? came back it reported by BS at 149 when actually it was 233. I checked again and it was 208. EIther way, too far of a gap. Yuck! Has anyone noticed accuracy start to slide after 7 days?
Also, I think the lag may get worse as the sensor ages. I have no proof of this but my arm was giving the best readings and they were spot on. I remember I would be 63 with a down arrow (meaning the Dex should be a little behind, so my BS should be even lower), and I'd check and be at 65 or so. I had several days of this spot-on behavior, even during BS changes it seemed. Towards day 6,7, and now 8, it seems they have grown further and further off. Any similar experience?
I do like the Dexcom because when its on, its AWESOME. However, I can see others' frustration with inaccurate readings, when to trust (or not to trust), and trouble in the evenings. For me, the verdict is still out. However, I know there are kinks that every user must learn to dealt with and learn how to work around, so I'm still in that stage I believe.
The software in Dexcom “smoothens” the data it reads from the sensor so that what you read on the receiver’s display is a very good approximation of what your actual BG reading is. This is the nice thing about the Dexcom!
Accuracy slides if calibrations are performed during times of fast changing of BG, so one should always delay entering a calibration reading in the Dexcom if there are big swings of BG due to food or other reasons. It’s always best to calibrate when the BG level is fairly flat.
I always use a sensor for two weeks, and when I restart it and calibrate it, I find that the readings are the most accurate. I always get 2 good weeks of readings from a sensor, and since I pay sensor from my own pocket, saving money is always a plus!
The readings in the higher range, above 180, can sometimes be off by up to 20%, but I don’t think it really matters, since you already know you must take action in order to return “between the lines”. I take a BG reading when I want to be sure, and very seldom enter that into the Dexcom even if there is a difference. There are more chances of “confusing” the Dexcom when one overloads the device with many calibration reading.
I just got mine too. Had the same issue with ripping it out after 4 days because of tape/itching issues. Now I used tegaderm…hope this works. What tape did you use?
Also woke up to alarm …decided to treat instead of test because I have been trusting this thimg. I did wake up pretty high so will not make that mistake next time. testing before treating is a good idea.
In general I’ve found that the Dex readings get closer to my finger-sticks during the second week.
When I start to experience multiple bouts of ??? readings, I cut my losses and change sensors. If it’s less than one week I call Dexcom and ask for a replacement.
As for the poor adhesion that you reported on your first sensor, I highly recommend checking out Skin Tac, a liquid adhesive that has allowed me to get 14 days out of every sensor.
Good luck. Your efforts to make Dex work for you will be worth it. I had a 1% A1c drop in the first six months of use. Better yet, the Dex has woken me up me during countless night-time lows, thus avoiding a multi-hour low and the subsequent hyper-rebound that extends many hours after I get up in the morning.
I’ve found that anytime my sensor goes to ??? (very rarely and usually not until around day 13+ unless it’s a bad sensor) then when it finally starts reading again it is off and takes a couple calibrations to get back on. It does the ??? because the readings it’s getting don’t make sense to it. This could be because the wire shifted, the sensor is dying, your body chemistry suddenly changed, or any number of things. It makes sense that when it finally finds a stable ground to read again it might not be entirely right on what that reading is because its environment has changed. I’d say if it takes more than 24 hours to re-calibrate properly then I’d give up on it but I wouldn’t be to worried about a couple bad readings after ???. Since yours seems to have taken a few days this might not be the problem. Also, we each have different body chemistry’s that eat through the sensor chemicals at different rates. Many of us find that days 8-11 are our best days but it might not work for you. Good luck in figuring out how to extend the sensor in a way that works with your body!
I agree with Rebecca, days 8-11 are almost always very accurate. If I’m lucky, days 2-12 are accurate. I have yet to experience a full two weeks of accuracy. I install a new sensor when the line takes on a very uneven look (one “dot” reading higher, next dot lower, etc.), which usually happens soon after day 12.
Use of Dexcom is part time in this house. We were getting a lot of off readings and ??? the first six months we used Dex but Dexcom was having bad sensor issues. In addition, when we got an off reading we would recalibrate. Not sure, but I think this may be a problem. Now if we have an off reading we wait a half hour or hour or so and see if Dex is reading properly again instead of recalibrating. We calibrate only two or three times a day max and only when her blood sugar is stable. Always calibrate her fasting BS, then after school BS (no IOB) and late night 1:30 or 2am BS if stable. Not sure if this has anything to do with better readings in general but by “stable” blood sugar, I mean no IOB but also in a semi-normal range (I try to calibrate when BS is in the 80 to 120 range). This was contrary to Dex technician’s advice. Her readings are really good now. Not sure if it’s due to Dexcom fixing the bad sensors, calibration technique or the fact we are not new users anymore. Stick with it; I think Dex will be more reliable within a six month period. P.S. Rarely pull a sensor just because of ???; just use Restart sensor and that will usually fix it. ??? are not uncommon at night due to the way she may be lying on her sensor; just shift position. Dex has a 20 percent variation, or can have. So at the higher numbers this can mean a 40 point difference; Dex is still reading accurate.
The MM CGMS reveals the BG/ISIG ratio which is a telltale sign of sensor performance. DexCom Gen4 sensors will have a lifetime indicator. I cross my fingers that the lifetime indicator will help with the dreaded decision on when to pull the sensor. My best sensor lasted for 16 days. A lot of them failed on day 13. Maybe this is because I am superstitious. My OmniPod has a 3 day cycle. I don’t like to change DexCom and OmniPod on the same day. This means that I want to use the DexCom for a multiple of 3 days. I tried 12 days. Last week my DexCom failed on day 12 while I was at work. Not desirable. I also noticed that after day 10 my DexCom has a tendency to flatten out. I decided to switch to a 9 day cycle.
Here is an update to anyone following my thread. I am currently on Day 12 and all is great!
I restarted the first time on Day 6 because I knew on Day 7 I would not be available to change the sensor, so I went ahead and did it early. Just went to “stop sensor” then “start sensor”, waited 2 hours, calibrated, and awesome! After that, Days 7-11 were probably the most accurate ever. When I first inserted my sensor I got several ??? periods, often lasting the entire night. I have not had those at all since the beginning and my readings have been spot on since then, particularly after my first re-start.
This morning (Day 12) I had good readings, then after breakfast I got ??? and it lasted for an hour. I did not want to wait any longer so I went ahead and hit “stop sensor” then “start sensor,” waited 2 hours, then calibrated again and it has been great all day. I’ve noticed that if you get the ???, stopping and starting the sensor usually works. It just stinks not having readings for 2 hours.
My sensor is on my arm and I will continue to use the arm because the accuracy is just amazing. However, I will fool around a bit with placement / location to try and find a way to avoid the ??? at night when I start a new sensor.
