Guardian 4 sensor

Has anyone tried this new Medtronic sensor yet? They say it is only for use on the back of arm. I cannot do that. I’m all thumbs trying it. Do you think it really would be different results just because of a different area used like abdomen?

That’s odd. They used to advise only on the abdomen area.

Waiting on my G4 to arrive, but don’t know why it wouldn’t work there imho.

The sensor is exactly the same as the Guardian 3 sensor. The difference is in the transmitter. In order to get FDA approval, they would have to test every different site and that is time consuming and expensive. Since they know many people prefer to use their arms, that’s what they went with for the Guardian 4. You can continue to wear them wherever they work for you. Just know that if you have to call Medtronic for any reason, tell them that the sensor was on the back of your arm or else they won’t help you!

I wore the Guardian 3 and the original Sof-Sensors on my arms only even though it wasn’t an approved site for those. I also didn’t use the backs of my arms because their sensors are so fussy I couldn’t tape them down myself or even remove the needle.

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Thank you. I wear sensors on my legs and they work perfectly. I hope these do too.

It sounds like you got some good tips regarding your question. If the G4 is like the G3, I’d suggest you try the upper arms, if Medtronic allows it in their policy. I had to use the back of the upper arm, due to inaccuracies, otherwise with the G3. With practice, I can apply it with just one hand, even with my left hand. I didn’t want to have to rely on anyone to help me. You have to use your fingers and thumb to manipulate it.

Also, I located a video on a Medtronic site that gives instructions for the G4, but by applying it to the abdomen. Hmmm……it’s dated 2021.

Really? I thought that was only Dexcom. When I was using the Guardian 3 I’d stick 'em anywhere. Even back of my calf, on the rec of some 670G bloggers.

Yes, at least that was what I was taught by my Medtronic trainer. I’ve typically worn them on the back of my arm except when i first moved from Dexcom to the 670G. I had an issue ONCE with Medtronic not wanting to replace a failed sensor because when asked about the placement, I told them my arm and they replied the sensor wasn’t supposed to anywhere besides the abdomen. Since then, on the rare occurrence I’ve had a failure, I’ve told them abdomen.

I think I read in the training literature for the 780G that the Guardian 4 is recommended for the back of the arm.

Just started using the G4 sensor last Friday after I completed the upgrade of my 770G pump. Been using Metronic pumps and CGMs on & off for much of the past 25 years.

Minimed/Medtronic has provided CGMs for the past 20+ years, and in all that time, they only “supported” using them in the abdomen. Using them in the arms, buttocks, legs, or other areas were never officially supported. Now it is only in the back of the upper arms, Seems a bit ironic that the most cumbersome CGM in the market to attach (multiple components, multiple layers of taping, etc.) is only supported in the most difficult place to insert it yourself without assistance. I look forward to when the Simplera hits the street to make this easier.

BTW … The G4 sensor is working fine after 4 days now. When I first started the G4 sensor, I still had a couple of days left on my Dexcom G6 sensor, so I left in-place so I could compare the readings. The readings were very, very close … many times they were the same value, but never more than off each other by 5 or 10. No finger-stick calibrations on the G4 sensor. That was impressive, and well beyond my expectations.


I just did my upgrade. So far impressed and happy I can benefit from the auto correct feature even while still using Guardian 3 sensor.
Are you still happy with yours? A1C improved at all?

Pretty happy with the 780G + G4 sensor/transmitter. Much stronger Bluetooth implementation in the Medtronic vs. Tandem. I have been in tech for a very long time, and the implementation of Bluetooth in the Tandem t:slim x2 is some of the worst I have seen in the last 15-20 years.

I have had good success with the G4 sensor/transmitter in my arm. I have tried it twice in my abdomen, and both times it hasn’t worked nearly as well. Seems odd since the G4 sensor itself is the same as the G3 (the transmitter is different), and I have very little problem with G3 sensors before I moved over to the Tandem last year.

So far, TIR hasn’t been as good for me with the Medtronic as it was with the Tandem. A little surprising with the auto-adjustments of the 780G. Was going to talk to my endo last week about playing around with my settings, but, a week before my appointment, I found out that he suddenly retired … really hated that - been with him for 25+ years. Now I have to wait for a while to get in with the ‘new guy’.

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What specifically didn’t work as well with the sensor in abdomen? More requests for calibration? Not accurate?
Also, about how often per week would you say it’s necessary to do a finger BG?
Thank you

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Keep in mind that I have used a total of seven G4 sensors … so, limited sample size.

The only time I have had to do a finger-stick calibration is with 2 of them, and only once after initial warm-up period. The others may have been off a bit right at the start, but they seem to ‘catch-up’ pretty quickly. The rest have been right on (+/- 5-10%) right from the start. Any other time that I do a quick ‘spot-check’, the sensor is well within tolerance from the fingerstick. Had the same experience with the Dexcom for the 9 months I was using it with the t:slim.

As far as the abdomen … it was odd. The 780G kept losing connection to the sensor. It would re-connect after a little while … more quickly if I took it out of the holster and moved it closer to the sensor. I wear the pump in a belt holster on my left side, and both times, I had the sensor in the right side of my abdomen.

I have not had that problem at all when I have the sensor in my arm, regardless of which side the sensor or pump is on.

I will probably need to do a bit more testing on this one … but seems a bit weird.

@RLR56, so did you switch from TSlim and Dexcom to Medtronic?

I had been using Minimed/Medtronic pumps for 25+ years, and had always been pretty satisfied with them (except for their first generation CGM). Was using the 770G, and waiting for the promised 780G upgrade for years.

Got tired of waiting, so last year the Tandem folks figured out a way with my insurance to get the Tandem/Dexcom approved even though I had another 1-1/2 years left on my 770 warranty.

So, I switched to the t:slim/Dexcom, and have been quite happy with them. But always wished that it would do more (anything) for raising glucose levels. So when the 780G finally got approved, I signed up for the free upgrade to see how it would be compared to the Tandem.

The upgrade process screwed up my 770/780 pump, but Medtronic switched it out without any problems.

Tandem vs 780G … jury still out.


My Endo retired mid-swap (770G->780G) too. Medtronic local rep has been helpful. I managed 96%TIR yesterday!

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@underarock, that’s incredible! I’ve been seeing others who are over 90% TIR too! I get so excited! I can’t wait! I’m working out the final details with my insurance now.

@HighHopes Yes, that was a good day. On average though, I’m averaging 91%ish. Worst I’ve seen was 86% so far, with 96% being my best.

I LOVE the fewer button presses and alarms on the 780G. The elimination of finger sticks is nice, but I’ve never been annoyed by them. Have also noticed when changing the G4 sensor, the pump seems to recognize the transmitter much faster than the 680G/770G did. Almost as soon as I “click” the transmitter onto the sensor, the pump recognizes it.


My Endo checked and told me that it is ok other than the arm- that’s just what they are trying to get us to use. I just started on the 780G last Saturday (was on 770G) and my son helped me put the first sensor for it on my arm. But my second one is now on my backside. With the 770G and G3 sensors I used my belly, backside, and even inner leg.