My experience with the new Medtronic 670G insulin pump

After 8 years of continuous use of my Medtronic Paradigm 722, I have replaced it with the new Medtronic 670G. This is the latest insulin pump technology from Medtronic. It provides a hybrid closed loop system that promises better management of blood glucose levels. Below I will detail my experience (both good and bad) using this system. Before using this new device, Medtronic offers a 2 hour group training class.  I attended the training and the 2 hour session lasted over 3 1/2 hours.  The class did give me some additional information that was not included in the manuals.

The first thing I learned was the Medtronic CGM sensor that is part of the 670G hybrid system is NOT covered by Medicare.  I asked the trainer how long before Medtronic would get it approved.  She said it was up to the FDA and didn’t know how far the approval process had progressed.  Interesting that the other CGM suppliers (Dexcom and Abbott’s FreeStyle Libre) are already approved by Medicare.  Also, both Dexcom and Abbott CGMs are FDA certified to provide BG reads that can be used for insulin dosing.  The Medtronic CGM is NOT certified so you still always need to do a finger poke prior giving a bolus insulin dose.

After using the Medtronic CGM for 2 weeks I can understand why it cannot be used to determine how much insulin to dose.  The CGM can be used continuously for up to 7 days before the sensor must be replaced.  I found it takes about 3 days of calibrating the sensor to get the reads to correspond to my BG meter.  Also, you cannot just insert the CGM sensor like an infusion set.  Instead you need a large hand held device to do the insertion.  You must follow a very intricate set of instructions to make sure the device works properly.

One thing I do like about the 670G is the backlight color display screen.  You can see it well in both bright sunlight and total darkness.  My old pump needed an onboard light turned on to view the screen when only limited lighting was available.

The Medtronic SmartGuard(tm) technology used in the 670G has what they call an Auto Mode.  This will automatically adjust your basal (background) insulin every five minutes based on your CGM reading.  There is a 9 point check list of requirements the must occur BEFORE auto mode can start functioning.  The main item is the requirement for constant BG meter readings.

After you insert the CGM, there is a warm up period that may last up to 2 hours before you get a prompt to enter a BG meter reading.  The BG read is used to calibrate the CGM.  After that you must enter a BG meter read at least every 12 hours.  Since the CGM BG reads are not accurate for insulin dosing, every time you do a bolus (like before breakfast, lunch, dinner and bedtime) you must also enter a BG meter read.  Medtronic recommends you use the breakfast, dinner and bedtime BG meter reads to calibrate the CGM.  Also, once Auto Mode is activated it will constantly ask you for even more BG meter reads.

In fact, after Auto Mode is functioning you may have to do BG meter reads 10 t0 12 times per day.  I found out from Medtronic tech support that you should NEVER use the BG meter readings prompted by Auto Mode to do CGM calibrations.  They told me that this overloads the calculation of BG levels by the CGM.

It seems obvious to me that the weakest part of the Medtronic 670G system is the CGM.  You would think that Medtronic would want the best available CGM to working with the 670G.  This would certainly make it better for all the type 1 diabetics that use Medtronic insulin pumps.  I guess they just want to maximize the profits they make from selling their own CGM consumables like sensors and transmitters.  What do you think?


  1. Wow, this article is good, my younger sister is analyzing such things, therefore I am
    going to let know her.

  2. I experienced the same with the Medtronic 670G closed loop system. I was not expecting the CGM sensor to require numerous BG meter readings. There is no likes to the Guardian Sensor in comparison to the DEXCOM CGM G5 which I previously used. I anticipate improvements with new releases in the future for the Medtronic CGM.

  3. I got my new Medtronic 670G pump and Medtronics CGM in September 2018. I had problems, too, with continuous need for BG readings to the point of removing the sensor during the holidays (with support from my Endocrinologist). During my sabbatical from using the Guardian Sensor I received notification (again through my Endocrinologist) that there was a transmitter recall. My transmitter qualified for the recall. I’m continuing my break from using the Guardian Sensor, until the new transmitter is available (they say “several” months).

    I would like to explore other sensor options during this time. It sounds like the DEXCOM CGM G5 or FreeStyle Libre might be options. Opinions please!!!!

    1. Hi Lucille,

      I’m no longer using the Medtronic CGM. I switched over to Medicare in August 2018. Medicare will not pay for the Medtronic CGM because the readings cannot be used for insulin dosing. Since both the Dexcom and FreeStyle Libre CGMs give readings that can be used for insulin dosing, they are covered by Medicare part B.

      In August 2018, I started using the Abbott Labs FreeStyle Libre. The only problem I experienced was the first reader I received failed to get the sensor readings after a day or two. I contacted Abbott Labs and they shipped me a new reader at no charge. The replacement reader fixed the problem.

      I’m very satisfied with the FreeStyle Libre. I have found the readings to be very much in line with finger stick readings. The sensor is easy to attach to the back of my arm. You don’t need to calibrate the sensor. Although you have to wait 12 hours after installing a new sensor before it will send BG data to the reader. During the 12 hour warm up, the reader can be used to read Abbott Labs BG test strips. I’m using the 10 day version of the FreeStyle Libre. I just discovered there is a new 14 day version on the way and it only needs a 1 hour warm up.

      I’ve read that some users say the adhesive on the sensor fails before the end of 10 days. This has not been an issue for me. In fact, I’ve experienced some bruising on my arm when removing the sensor after it expires on day 10. Also, there are adhesive covers available that can be applied over the sensor so it will stay in place for full 10 days.

      The only other issue for me is the sensor must be applied with a large plastic/electronic device. The device can only be used to install the one sensor. I hate to have to put it in the trash after just one use.

      The main difference between the Dexcom and the FreeStyle is the Dexcom will trigger an audible low BG alarm. If you are low BG unaware then the Dexcom would be the better choice for you. I was low BG unaware before I started using an insulin pump. I believe this was caused by the long acting insulin used to control basal BG levels. Since the pump uses fast acting insulin for basal BG control, I now have no problem recognizing low BG levels and taking steps to raise my BG.

  4. Thanks for this article! I am an Animas insulin pump user with the Dexcom G4 (I will be switching to the G6 this fall). Prior to 2016 I had tried the Minimed CGM with the Minimed 523 insulin pump and gave up on it due to poor performance. I must switch back to Minimed for 1 year in September because Animas partnered with Minimed when they closed up shop. Because of all of the problems I have read about the 670, I will definitely not choose that device. I will stick with my Dexcom and use the Minimed Paradigm pump for 1 year. I am hoping in 2020 to switch to Tandem Tslim.

    1. I had a terrible experience with the Tandem Tslim. The cartridge is actually just a little plastic bag inside the cartridge that is tedious to load. I experienced a lot of errors with my pump, and delivery issues. this pump does not have a syringe inside the cartridge that glides..a little bitty plastic bag that dependent on you getting the load perfect and you will not know this until you start experiencing issues, high blood glucose because you cannot see the little bag to know if all your insulin went into the bag. I did not have a good experience with the pump and I personally don’t recommend it. but, each to his own, and I wish you the best of luck with it.

  5. I got a 670g and don’t care for it. With the sensor working I have to check my blood sugar too many times per day. I might as well not have a CGM at all. It seems as though I’m being sabotaged daily!

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