Minimed 670

I have to say my experoence with the minimed 670g has been terrible… i have only been on the sensor for 1 week and have had to change it 3 times becauae it just stopped working… i am so beyond frustrated…i had to wait a whole year to get this machine and now that i have it i still cant benefit from it. I am so upset. I have been t1 for 27 years and was really looking forward to something thatvwould help me and still nothing is good.


sorry to hear about the bad experience. not everyone can benefit form a CGM. Many people have trouble with CGM reliability and accuracy. The CGM simply doesn’t work for a few people. I suggest that you contact Medtronic customer service and ensure you are doing everything possible to make the CGM work.

The pump can still be used as a pump - it just won’t have automatic background insulin function (because that automatic function needs the working CGM). So it’s no different than your old pump - if you were a pumper before.

I’ve had a similar experience Samantha. I was so excited for the 670G but it’s really limited. The CGM is fussy & too high maintenance for the benefit it provides. And the pump auto mode just smooths out basal rates.

My basal rates were already accurate… I thought the pump auto mode would help correct bad carb counts or other issues that pop up, but it really doesn’t do that. So now I’m stuck with a heavier pump that requires a million button pushes. Think this pump would be good for a newer diabetic or for a child.

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The MiniMed 670G is my third CGM system. It’s a mixed bag. My experience with both the Dexcom G4 and G5 was that they were accurate, but the receivers were unreliable with alerts. Using the G5 with my phone was both accurate and reliable.

Now I have the 670G with the Guardian 3 sensors. I was ready for bumps in the road with a new technology. But I agree that it’s mostly frustration three months in. There are some design issues I could gripe with, but I will share my sensor experience that relates to the original post.

When the sensors are working, everything is awesome, including accuracy rivaling the Dexcom G5. However, I have found that only about 30% of the sensors function accurately and last 6-7 days as designed. Usually, they reveal themselves to be duds within 1-3 days. My blood glucose will be twice as high as the sensor thinks. I will get false low readings, suspended micro-boluses (basals), then higher highs due to insulin deprival.

Then I have to call Medtronic to troubleshoot and get replacement sensors. Almost every week. High maintenance is exactly right, Jennagrant. It’s the opposite of what we hoped for with a closed loop, which is less mental and emotional attention devoted to T1D.

Joe, my experience is something besides a CGM compatibility issue. The Dexcoms worked great for me. The calibration factor settings seem designed to make my sensors fail. I am willing to work with Medtronic to improve things. If it lives up to its potential, wow.

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Soooo…i just spent over an hour on the phone with a minimed tech…as i had my 4thsensor stop functioning on me in a less than 2 week time frame. He tested the transmitter and we determined it was good…but the batch of sensors could possibly be to blame… he did give me some great tips that i will share…

  1. Do not calibrate if your blood sugar vs your sensor sugar is greater than 20% different.

  2. Take your blood sugar and divide it by your isig number (found in the sensor statua menu) if the result is between 2-16 you are good to calibrate…anything outside that range is not the time to calibrate.

  3. If your blood sugar is off by greater than 20% turn off the sensor feature for 3 hours, get your sugars inline manually, then restart your sensor.

  4. If your not in a calibratable reading…ie. thw isig computation is outside of 2-16, or your sugars habe an arrow (so rapidly changing up or down) then snooze thw calibrate for 1 hour.

  5. If your get a calibration not acceted error… do not do the 2nd one in 15 mins…wait 1 hour beforw trying again.

  6. Call them, and they will troubleshoot/confirm these hints. They really are lovely there.

818-576-5400 is the 24/7/365 ph. For the tech team.

I have renewed faith in this machine…I will let you all know how my newest sensor works in hopefully 6 -7 days…if it collapses on me in less time…I will let you know of course.

Be healthy Be happy.

I find myself quite surprised to hear about so many people having issues with the Medtronic 670G and the CGM that goes with it, simply because I’m on that system and I’ve been on it for about 6 months and haven’t had more than a couple sensors fail, and most inaccuracies I could trace back to a bad calibration or lack of. The tips that Samantha provided are very true and very helpful, but I’ve haven’t really had to use many of them in my experience.

That makes me curious where the differences between us arise, because I have put so much trust into how effective this system is that I imagined that others were having similarly positive experiences.

I and hopefully others will vouch for the system once you work out the bugs and kinks, which I hope you’re able to do quickly.

Sometimes I think that Medtronic would be better off partnering with Dexcom, but Medtronic is one of the few CGMs on the market (other than the new Freestyle Libre) and having “options” (even though the Guardian Sensor 3 only works with Medtronic pumps) is nice.

Sensor #5… following every tip… only been on sincrme sunday evening. It is now 2 am on tuesday morning …so not even 48 hours amd this piece of garbage is now senor updating. Are you friggen serious!!!

This is crap. This product cost me ALOT of money and it doesn’t work. Like at all!!! I am going to be looking into contacting the FDA to open an investigation into medtronic and their product production and testing practices.


The current (and best) CGM technology does not work for some people. at all. Others find that even though it does work, it’s inaccurate. Still others will find that a CGM is not worth the trouble, or that they don’t like it for other reasons. Then of course, there’s the group that find the CGM is great, works great, and they like it. if nothing else, at least you know where you are at.

here is information regarding medical device reporting - although the FDA is really only concerned with “adverse reactions” you can use the following to report malfunction (literally: “bad function”)

How to Report a Medical Device Problem:
Medical device reports are submitted to the FDA by mandatory reporters (manufacturers, importers and device user facilities) and voluntary reporters (health care professionals, patients, caregivers and consumers).

Mandatory Reporting for Manufacturers, Importers and Device User Facilities (Form FDA 3500A):
Find information and instructions for mandatory device reporting at:

Reporting Medical Device Adverse Events for Manufacturers, Importers and Device User Facilities
Instructions for Completing Form FDA 3500A
eMDR- Electronic Medical Device Reporting
Medical Device Reporting for Manufacturers - Guidance for Industry and Food and Drug Administration Staff
FDA Guidance: Medical Device Reporting for User Facilities (PDF Only) (PDF - 313KB)

For Questions about Medical Device Reporting, including interpretation of MDR policy:

Call: (301) 796-6670
Or write to:
Food and Drug Administration
Center for Devices and Radiological Health
MDR Policy Branch
10903 New Hampshire Avenue
WO Bldg. 66, Room 3217
Silver Spring, MD 20993-0002


imo, “so many people” is a tough call… it’s human nature to be vocal if you are upset, so the complaint hotline is typically busier than the “compliments” hotline.

the clinical results of the 670g was positive for the majority of the population of 1500 people in the trial… otherwise there’d be no 670g!

Thank you Joe this info is helpful.
I def would say I have an adverse affect … as tge machine thinks my sugar is going low and suspends my insulin and then in real lofe my sugar is in excess of 300… so yup that would be very adverse.


there is no reason to have your auto suspend turned on when you know you have sensor problems. if you are uncomfortable with your settings please reach out to your endocrinologist. if you know how to change your settings and are comfortable doing so… you can turn off auto suspend.

Obviously. That was before i knew there was a sensor issue. But thanks for you input.

Thx for the tips. Been on Medtronic pumps for nearly 20 years, didn’t know the isig 2-16 thing. I do find there to be some frustrating calibration issues at times… definitely!

Update based on my experience: if you are having sensor problems, try experimenting with sensor location. I have had much better results (no duds and good accuracy by day two) by placing the last three sensors on my thighs. The abdomen site just doesn’t seem to work for me with the Medtronic sensors. Abs were fine with the Dexcom sensors.