I know several people wear there sensors more than a week. I have tried 3 times to extend it to 2 weeks and can not get it to work. I carefully un-tape the transmitter and charge it and try to carefully put it back on and re-tape and after a day it flakes out on me usually getting lost sensor messages and then a change sensor message. What am I doing wrong?
Thanks Lori
I donât know what CGM you have, but I use the Dexcom G4 and if I want to use the same sensor for an extended period of time I leave the sensor and the transmitter on. Iâm not aware of how the transmitter could be taken off and charged if possibly you are using a Dexcom? I just confirm on the receiver that I have replaced the old sensor with a ânew sensorâ even though I really didnât and then wait for the 2 hrs start-up to finish. I never remove the transmitter when doing any of this as well.
I am on the enlite sensors and have been told transmitter battery only lasts for 6 days.
Oh,okay. The Dexcom G4 transmitter lasts 6 months. Hopefully someone who uses Enlite will respond to your question!
My personal opinion is that the biggest problem with the Medtronic Enlite CGM technology is how finicky it is. When it works it can work quite well. But it does not take all that much to throw it off track.
Removing and reattaching the transmitter without jostling the sensor probe or disturbing the overtape holding the sensor in place can be difficult to do. Could your problems possibly stem from disturbing the subcutaneous sensor probe even though you tried very hard to avoid doing that? Who knows?
However, whether or not you are âcareful enoughâ when removing and reattaching the transmitter, should not have any connection with getting a âlost sensorâ message. The performance health of the Enlite sensor is mostly irrelevant. All that matters is that the transmitter thinks the sensor probe is pretty much properly inserted in your body and that a usable radio connection can be made between the transmitter and your pump.
A weak or lost signal in my case usually means that there is something physically obstructing the radio signal. Unintentionally allowing my body to come between my pump and the transmitter will often block the signal. I âfixâ this by moving the pump closer to the transmitter.
If your MiniLink displayed the 6 flashing green lights within a minute of reconnecting it to your sensor, then it thinks the sensor is inserted and it should connect to your pump. If you do get a âweak signalâ alert, moving the pump next to the transmitter should allow it to connect it again.
The question which came to mind when I first read your post was what are your Calibration Factors (CF) prior to attempting to recharge the transmitter? I base my speculations about the health of the sensor I am currently using on what CFs the pump is coming up with when I calibrate.
Often I will do a calibration about a 1/2 hour (or more) prior to removing the transmitter just because I want to see what calibration factor the pump is using at that time. If the CF is not what I personally consider âgood enoughâ then I wonât even bother to try to extend.
My opinion based on my personal experience is that if the pump comes up with a CF of 6 or more that sensor is probably dying. If the CF is between 5 and 6, then ehhhhh, I donât know. 
Iâm not optimistic and not sure it is worth the trouble of trying to extend. If it is still between 4 and 5 then I would consider it to still be performing nominally and might be worth trying to drag a few more days out of it.
Do you know how to use Medtronicâs CareLink website portal to obtain a report of the data from your pump which will you show you what Calibration Factors the pump is using with your sensor?
The other direction you might want to go in is to check your transmitter for problems. The next time you change your sensor you could test your MiniLink transmitter using the test plug which came with it. It takes about 10 to 25 minutes if I recall correctly.
If the Medtronic HelpLine has never walked you through doing this, I have listed the steps for how to do this in this thread: How to test a Medtronic MiniLink CGM transmitter & why you might want to. Of course, you could also simply call the HelpLine and then ask the rep to walk you through this. The steps are also listed in the full user manual for the 530G pump (or the Paradigm Revel pump).
The transmitter which Medtronic uses for their CGM is rechargeable. The charge should last at least 6 days, but, in my experience not very much longer than that. As a result, if you want to try to extend the life of a sensor you need to very carefully remove the transmitter, recharge, and reattach.
By contrast, the Dexcom transmitter uses a primary, non-rechargeable battery so you can just leave it in place when renewing your sensor.
Could you explain how to let Carelink show this calibration factor, John? Canât find it in the PDFs I got from Carelink. Thanks.
(Edit) sorry was reading with my ears. Needed to read the extended logs in personal care link. (/edit)
P.S. I am on day 22 of my current sensor - breaking personal records 
I think what you are saying is that you figured out how to include the pump calibration factor in the PDF report you create with CareLink.
However, I am not really sure what the reference to either âextended logsâ or to the âpersonal care linkâ are about. So, for whatever itâs worth, I am tossing out a screenshot or two of the CareLink report settings I use to include the calibration factors the pump calculates in my reports. I expect it is probably what you are already using, but what the heck, eh? 
Below is a screenshot of the CareLink reports screen with the âData Tableâ report selected (highlights). The content of the report is controlled by selecting the various check boxes in the middle of the screen. In order to get the calibration factor data, you need to select at least the Pump and sensor diagnostic info checkbox.
In the screen capture I have highlighted both that checkbox and also the Sensor Data checkbox because, in my opinion, itâs a lot easier to figure out what the heck is going on when you include the Sensor Data. If you select only the Pump and sensor diagnostic info checkbox and not any of the others, you will get a report similar to the screen cap below.
If all you want is a report with only the Calibration Factor data, then thatâs all you need to check, I guess. But I usually prefer to have a bit more context to give me more insight into what may have been going on at/around the time I did the calibration. So I almost always select all of the checkboxes as is shown in the first screenshot above.
One final note. In the first screenshot I have also circled the button for selecting a âData Export (CSV)â report. You can also obtain the pump calibration data from this report. However, the CSV or Comma Separated Value report is a lot less friendly. It is just a dump of all of the pump data organized into spreadsheet columns. Itâs probably the best way to go if you want to really dig into the data and crunch the numbers in some way. However, I think it would confuse most people. I am only bringing it up as an âFYIâ.
I almost never get them to last longer than 6 days. It has happened, but almost never. dexcom sensors last longer than a week all the time.
Mine donât always last an extra six days but this is what I do (I have Enlite 2, and Medtronic 640G):
On the last day of the current sensor (BEFORE it tells you to put a new one in) I remove the transmitter and put it on charge.
Once charged, I reconnect the transmitter to the sensor and select âStart New Sensorâ.
Warm up generally works as normal, and I can get between 1-6 extra days. My record was about 24 days.
Itâs important to do it before the sensor âexpiresâ and to select âstart new sensorâ otherwise it wonât work. I generally do it in the last 12 hours of a sensor.
Hope this helps!
Thanks so much. I will definitely try it.
Lori
I donât know how you figured this out but it worked this time. On the 5th day I charged and re-taped and it is doing well with a high isig number too. Thanks so much. I am very excited my copays on the sensors are pretty high so if I can get them to last 2 weeks I will be thrilled.
@Lori31 Iâm glad it worked! I donât know if I found it by accident or if I read it somewhere haha! I only got 10 days out of the last one, but Iâm happy with that
