Medtronic cgm: anyone use this before?

I just received my newest Medtronic pump, and it is compatible with either the Medtronic CGM or the Dexcom. I have had terrible experiences with the Dex and was wondering if anyone has ever tried out Medtronic’s CGM and what their experience was like.

I look forward to hearing back from you (anyone, even if its only word-of-mouth)



PS: btw, the new pump model is the 670G

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DM, I have heard a lot of comments about how inaccurate the Medtronic CGM is compared to Dexcom.


Daisy, I am not at all sure what you are saying here. I am not aware of any currently available or announced Medtronic pump which supports using Dexcom CGM.

Yes, you can use Dexcom CGM while you are using a Medtronic pump. However, none of the automated features which the 670G provides will be supported. For the 670G pump to be aware of your CGM results, you will have to use Medtronic’s CGM.


Thank you. I must have misunderstood what the tech rep was explaining to me. I thought that the Dexcom could be connected somehow (it didn’t make much sense to me either. I was very clear that it could not be connected with my FSLibre though…which sucks anyway and is never accurate enough to bolus over, much less used as any type of IQ pump system!!!)


DM, I have known you about 5 years. I’ve watched your adjustments, seen your note-taking, seen how you do things, see how you get mad when your BG goes up, seen how happy you get when your A1C result comes back.

After all these years I know you really well!

I feel confident in saying this - the Auto Mode in the 670G is not for you. Keep it in Manual Mode and you will be much happier.


I know this!!! Without a doubt. I dont think I could take one hour of having some inaccurate, unreliable system taking over the responsibility from me. And Truly, I dont know how someone like TRYING does it. I would totally have a meltdown :weary: :rofl: :crazy_face:

I was simply wondering if ANYONE has tried out the Medtronic CGM and what their experience was like. I remembered hearing it was awful, but wasn’t certain. And, btw, I gotta get off this stupid Libre, bc it just doesn’t help with anything. Perhaps the new Dex G7 might work for me. Perhaps its worth waiting for. Any thoughts?


Did you consider a different pump?
If not, why did you pick Medtronic.


That’ll be about a year’s wait, last I heard.


The Medtronic CGM for the 670g are called guardian sensors. I have used the 670g with guardian sensors, and I currently use the tandem t-slim x2 with dexcom g6 sensors. There are comparisons that others in the FUD community have made that you can find by using the search tool here on FUD.

Do you have specific questions about the guardian sensors?

My general overview (if I’m remembering correctly - this may have changed since I used the 670g with guardian sensors, but I don’t believe so) : the guardian sensors last 7 days but take a day or 2 to get accurate, in my experience. The transmitter must be charged in between changing sensors (a few hours+ I think). Insertion hurts more than dexcom IMO. Guardian sensors must be calibrated at least every 12 hours but sometimes more frequently. If not close to the sensor reading, the calibration can cause the sensor to fail early and require replacement I think. The amount and frequency of alarms while using the 670g+guardian sensors were a lot and oftentimes very frustrating.
From my experience, guardian sensors can get inaccurate and have transmission/reception issues in the last day or so. From my comparisons, I think the guardian sensors were ok on accuracy, less accurate than g6 mostly, especially when BGs were moving up or down quickly. But I think I remember the guardian being better or ok in terms of accuracy for lower BGs for me, but I’m not entirely certain on that.

Of course, this experience depends on the individual, their preferences, and their expectations of control. Hopefully the 670g and guardian sensors work well for you!


Thank You Larissa for all the helpful info. I dont plan on ever going on this sensor. I was merely very curious bc when I was ordering the new 670G, the Medtronic rep asked me if I were using it already or if I were interested in using it. From all I have heard about it and read, it sounds awful.

I would rather do 50 finger sticks a day than go on a completely useless and inaccurate cgm. I’m using the Libre 14 day now for a couple of years. Its terribly inaccurate, but consistently so, if that makes any sense( it generally runs 20 points lower than a finger stick, and thats rather reliable).

anyway…thanks for your input. greatly appreciated.


The very old Medtronic pumps can be used in closed loop with additional equipment and dexcom sensors. This is what started the early “we are not waiting” home grown closed loop systems.

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I’ve been using a Medtronic CGM starting with a Guardian, then a 630G and finally a 670G. I recently switched to t:slim X2 with Control IQ using Dexcom G6 sensors.

The Medtronic CGM sensors are accurate enough but do require calibration every 12 hours (or less). I was usually doing 4 per day, breakfast, lunch, dinner, and before bed. If I was out for a meal, I’d skip that calibration. The Medtronic transmitter requires recharging at each sensor change (latest sensor is 7 day). I could often do the transmitter recharge and then tell the 670G to start a sensor without physically changing it. I had some last 14+ days but I usually changed at 14 when it went that long, I think the average was around 10-12 days. My reason for extending the sensors was because Medicare wasn’t paying for them, I was (they have a cash price discount).

I switched to Tandem / Dexcom because Medtronic’s “next generation” pump/cgm (790?) isn’t ready yet and Medicare pays for the pump, pump supplies, G6, and G6 supplies. I do like the Control-IQ algorithms better.


Thanks for the write-up @bsmorgan. Nice insight from someone who has used both systems. Welcome to FUD.


I have the 670G and it is NOT compatible with the Dexcom. If you want to use the CGM, you must use the Guardian CGM.

Personally I hate it. I wish I had kept my Dexcom G5. I would have to manually enter my numbers and would not be able to run in AutoMode, but the Guardian sensors are so unreliable.

It would be like having a standard pump and CGM like I had before. I like AutoMode, but find that it’s cranky and because of the unreliable sensors it isn’t always working the way it should.