How I use my sensor

There’s a lot of frustration over using these thing, and rather than post in one topic I thought I’d share what works for me in a new topic. Please reply with what works for you. I was ready to give up, but after doing a lot of reading and trying things, I feel I’ve got it down. Here is what I learned.

I started in my abdomen, but never got a sensor to work. I actually never got to the point where I could calibrate without lost sensor errors. I now exclusively put them in my thigh. I may try the abdomen again (see next topic)

Starting a sensor:
This is the toughest part. I put a new sensor in, 40 minutes later plug in the transmitter. If I get a lost sensor or now signal, I unplug, plug back in, and start new sensor. Usually after two hours of this till I get to where it won’t fail (another two hour wait till calibration).

Age of sensor:
OK I don’t recommend this, but this is what I do. Start my sensor on Saturday. On Tuesday I get the Sensor end. I just hit start new sensor (don’t have to wait 2 hours as it asks to calibrate in a few minutes). Go thru the same process on Friday (same sensor). On Saturday I unplug the transmitter and charge. Replug to same sensor and calibrate after 2 hours. I do this for 3 weeks, so yes, I’m using my sensor for 21 days. For whatever reason it acts a little flaky on day 10, but it works better on day 20 than it does on day 1

I go this long because 1. I’m paying for the sensors, and 2. They just start working accurately on the 2nd day.

This thing has been great for me. I can’t imagine being without it.

Thanks for your input and detailed “how to”. I’m new to CGMS and have been trying new things along the way. I have read that the sensor and the pump each have their way of “ending” and I have also restarted, recharged and restarted, etc. So far, though I only pushed to 7-8 days. I found it was easier to always restart as a new sensor, rather than to find a lost, or reconnect a lost sensor. With my next sensor, I’ll try your cycle to see how it works.

As far as placement, I’ve had the best, most stable, readings from my triceps. I found my stomach to be uncomfortable and that I had to “baby” it with moving around, etc. I also tried it on my lower back (which was by far the most comfortable place - and will probably try it again), but I would always get a “lost” sensor when laying down on the couch.

I would be excited to get 21 days. I am in the process of switching insurance carriers and fear that my new company won’t be as liberal as my previous. That would stretch out the supply I have as I work through the new insurance game.

Do you sleep on your back. I’ve heard others say they use the triceps area, but I’d get a lost sensor since I sleep on my side. I only use the start new sensor as well. Haven’t found a use for the others. Wat do you use to cover your sensor and transmitter? I use the Nexcare Absolute Waterproof Premium Adhesive Pad 2 3/8" x 4". They seem to work well, but are a little pricey.

Brian: Great information. Thanks for posting it.

I started with the sensors on my stomach but found that they would not stay there because of the hair, and shaving my abdomen lead to lots of itching when the hair grew back in. Now I use the upper thighs.

I rarely use a sensor for more than 7 days. The longer it is in, the long it takes for the spot to heal. Have you had any problems with that?

The big problem I have is with lost sensors or weak signals. I have found that there needs to be nothing solid between the transmitter and the pump to avoid getting lost sensor alarms. This often happens at night, since I often sleep on my stomach, which means my body is between the sensor and the pump. But, it also happens, say, if I am reading a book and the book happens to be in the way.

I use the IV 3000 pads. They barely cover the sensor and transmitter, so I need 2-3 each time, and the tend to rub off if anything rubs against them.

I actually lay on my CGMS sensor all the time along with my pump. I am so used to doing that I don’t think I could change if I wanted too. I think the warm up period is very important and so far 8 days is longest I have been able to stretch my sensor life. I use the IV3000 prep tape to hold my sensor in and it really works well. Of course I have to bust out the lighter fluid to clean the sticky of my transmitter but all in all CGMS is pretty nice. I find that it can be a pain when I am wearing sometimes but when I take a break I find myself missing it!! I agree my sensor acts nutty on day 8, I usually get a weak signal reading and then I get rid of it because the area where it is inserted starts getting itchy.


I was surprised when I first took the sensor out after 21 days. It wasn’t sore, but it does take a while to look “normal”; usually 2 cycles, so 42 days. No matter what I get weak signal after 7 days (2 sensor ends + 1 day). But I do a recharge and all is well. If my body is between the sensor and pump I get a weak signal. Funny thing is, I play tennis with my pump on the side line. I get weak signal alarms but when I’m done never had interruptions in readings.

Ya, it’s funny I went 17 years with BG readings 1-3 times/day, and now I feel I’m in danger during the calibration period!!

I was at the Doctor today and he said Medtronic is working hard on closing the loop and on an implantable pump. He said it would be in the abdomen and you’d have to come in every 2 months to get it filled. Not sure I’m ready for that.

Great thread! I was so frustrated with my Medtronic CGMS for the first month or two until I learned a lot of these same tricks…

After the first 2 sensors I have never again used my abdomen (seems like most of us are in agreement on that one). They work okay on my butt cheeks but I’ve found that I get really accurate readings on the backs of my arms and in leaner areas so I mostly rotate through arm sites until they start looking battered… I sleep on my back or on one of my sides, my sensors don’t usually get disturbed when they’re on my arm but I tend to sleep on the side opposite of where I have the sensor.

I usually pull my sensors on day 8 or 9, but sometimes I recharge and keep them going - I kept one going almost a month once but got a little bit of scar tissue. That sensor was incredibly accurate and still going strong on day 26 - I actually pulled it because I was worried about the skin underneath. I’m going to pick up some OTC scar treatment to see if that helps, it would be great if I could routinely leave sensors in a month without doing permanent damage.

I use IV3000 to cover the sensor/transmitter, Tegaderm works great for me as well. Whenever I recharge the transmitter I wipe down the area under the transmitter/adhesive with alcohol and also scrub the transmitter with alcohol and a dry washcloth until all the adhesive is gone. This usually takes at least a couple alcohol swabs and is sort of a pain in the ■■■. David, do you really use lighter fluid?! I imagine that might work pretty well.

Yes I really use lighter fluid. It breaks down the sticky adhesive right away and dries very fast. It does not leave any residue on a nice clean transmitter. I have yet to try my arms but I am sure I will at some point.

I just had a bad sensor the other day. I recommend to anyone who uses the Medtronic CGMS to call the 24 hour help line. Even if you really do know that the sensor is bad and you have tried all the tricks. I am getting a free replacement for my bad sensor and this is my 2nd replacement that I have gotten from them. My insurance pays for almost all of it but those sensors are expensive and thankfully Medtronic stands behind their product and replaces them.