MiniMed 670G is Inaccurate

For the past 10 months I’ve been using the 670G, touted as the first closed loop insulin pump system by MiniMed. I was so excited to try out the 670G but the excitement wore off very quickly. Aside from the constant requests to “Enter a new BG for Auto Mode”, the accuracy of the Minimed 670G is inaccurate.

670G Inaccurate BG Readings

Here’s an example of one of many inaccurate blood glucose (bg) readings on my MiniMed 670G pump system and more.

After waking up last Saturday I looked at my 670G pump and it said my bg was 128 mg/dl. However, when I checked with my Contour glucometer, it said my bg was 171 mg/dl. I checked again with a finger stick to be sure and it said the same 171. That’s 43 points off and totally unacceptable. Also, more then the 20% off that MiniMed says the system allows. There’s been many other times my bg readings were off by more than 20%. Two weeks ago around 10am and only having one cup of coffee (without sugar), my pump said my bg was 117, however, when testing with my tester, it said my bg was 197 mg/dl. Let me reiterate, I always test my sugar more than once when it’s off by this much. I even spoke to support regarding this inaccuracy issue and they say there’s nothing wrong with my system. I find that hard to believe! If this is the case then the MiniMed 670G is inaccurate and not trustworthy for me.

Guardian Sensor 3 and Guardian Link 3 Transmitter

The 670G uses the Guardian Sensor 3 and Guardian Link 3 Transmitter for its continuous glucose monitoring (CGM). This CGM system is suppose to be accurate and a rival to Dexcom’s G6 CGM. I have never tried the Dexcom G6 but all the literature I read and heard about it, is all good and extremely accurate. As far as the 670G’s Guardian sensor and link CGM, it is very inaccurate in my experience. Keep in mind, I’m an insulin pump user for over 20 years, I know how to count carbs, use pump functions and also very familiar with the 670G system. It seems like the most important task with the 670G is to be spot on when counting carbs. If you under estimate your carbs you won’t bolus enough and the system can’t correct it with the micro boluses.

My 670G Conclusion

I guess you can say this is my MiniMed 670G review or just me venting about the system. Either way, my conclusion is the MiniMed 670G closed loop insulin pump system is inaccurate! Looking forward to switching to an improved autonomous insulin pump system or Tandem t:slim X2 in the near future using the Dexcom G6 CGM. #670g #670greview


I’m a type 1 diabetic with diabetes knowledge in t1d and t2d, as well as nutrition and low-carb keto diet information, fitness and exercise programs to help keep you in optimal diabetes health. Take advantage of our diabetic health tools for a healthier lifestyle!


  1. Fxrjoe November 25, 2020
  2. Justin B July 11, 2021
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