My thoughts exactly on the calibration time - yikes! I miss my Dex 
. And I had the same issues at night: thinking I was 40, shutting off, and waking to 500+. Counting down the days until the new one, for sure! 
Good luck!
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Hi All. A few important bits of information/corrections:
- The 670G uses the Guardian Sensor 3 with the Guardian transmitter, not Enlite Sensors. The 630G, uses the Guardian Link transmitter with Enlite sensors. It’s a big difference.
- As for the MARD comments, MARD is a testable result and I can say without question for me that the Guardian Sensor 3 is VERY accurate and is the ONLY one the FDA trusts to manage a hybrid closed loop system. ref: Sensors & Algorithms for Continuous Glucose Monitoring: Accuracy Requirements for a Hypoglycemia Detector: An Analytical Model to Evaluate the Effects of Bias, Precision, and Rate of Glucose Change - PMC
The Dexcom G5 and the Guardian Sensor 3 have a delta of .64% for MARD, less than 1% difference in accuracy. Those statistics can be found on each of their websites.
Source: https://www.medtronicdiabetes.com/products/minimed-670g-insulin-pump-system
Source: https://provider.dexcom.com/education-research/evidence/clinical-studies/single-digit-mard-demonstrated-software-used-dexcom-g5
Personally, I did have some inaccuracies on the Enlite sensors. However, since switching to the Guardian Sensor 3, I have found it to be incredibly accurate, more than I could have imagined. So many people I’ve talked to have been reporting unicorns (either a flat SG line for an extended period of time or a perfect SG-BG match).
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Just got a call that my 670 is about to ship. Can’t wait!
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I’ve been a long time Medtronic CGM and pump user. Because of the Medical department where I worked I was extremely blessed to be able to try different pumps and CGMs before plopping down my hard earned cash and insurance money for something. I did try the Dexcom a few years back and it was more accurate than the Medtronic at the time, the hassle factor of carrying around more crap with me everywhere I went kept me using Medtronic. The Enlite sensors with the Guardian transmitter were pretty accurate and I only had one bad sensor in 7 months. So far the Guardian 3s are even more accurate!
Probably the hardest thing for Dexcom users to adapt to is the more rigorous calibration requirements for Medtronic sensors.
I think the closed loop 670G is a slam dunk for Medtronic but for diabetics used to other pumps and CGMs it takes some getting used to.
Another thing I learned in my Diabetes classes is the difference in how Medtronic sensors measure glucose. They measure the glucose in interstitial fluid and there is a difference between blood glucose and sensor readings. Generally by day 2 the pump figures out how to correlate the bg reading and the sensor readings and becomes much more accurate.
Not just Medtronic, Dexcom does this, too. The difference you’re describing is between subcutaneous “glucose” sensors and fingerstick or lab blood glucose tests.
I hope you’ll continue to provide updates on the Guardian 3 sensors and 670 system in general. Have you had any false lows overnight that caused your pump to entirely shut down insulin delivery and led to hyperglycemia?
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The 670G will stop before a low occurs but monitor and restarts when glucose reading becomes within range for continued insulin delivery and adjusts to prevent highs.
On the 670, which I’ve had about two weeks I had a false low once while in auto. I have a meter that I keep in my nightstand so I verified the correct reading and recalibrated.
Mildly annoying but it straighten out.
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The Dexcom g5 is approved for bolusing
Suuzan
Your g5 sensor is incredibly reliable once well-wetted and fully calibrates itself over about a half day or less. Wish I could say your receiver is good, but I can’t. It’s junk.
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I got my 670G several months ago, but you will definitely be getting the Guardian 3 with it. The reason they were even allowed to add some of the features such as Auto Mode to the 670G is because of how much better than Enlite the Guardian 3 is. Without the improvement going from Enlite to Guardian 3, some of the features in 670G would not have passed FDA certification.