Medtronic 670g System

We’ve been using the newest technology in the pump/cgm world for about 4 months now and here are my opinions.


It’s accurate. When TJ wore both the guardian sensor and the Dexcom G5, they were both (usually) pretty close to finger pokes. I feel that the guardian caught the lows a little faster and that the g5 recognized the highs faster. In my opinion the guardian sensor was just as accurate as the G5 (which was not perfect).


Auto-mode has really leveled out TJs blood sugars. He has way fewer mountain ranges on his cgm graph and lots more leveled out days and nights. In fact his A1c has dropped a whole point from 8.6 to 7.6 in those 4 months. So I think auto-mode is awesome! When it doesn’t kick us out. It kicks us out if he’s high for over 4 hours or low for over 2 hours. It kicks us out if the sensor isn’t reading for any reason (missed calibration, sensor is confused because it’s day 5 or 6 of 7, it’s in the dreaded need bg loop). Auto-mode is not a cure. It’s not infallible. It’s not perfect. TJ still has lows in auto-mode. He just needs fewer carbs to come back up into range-usually 4. He still goes high, if his carb ratio is not aggressive enough, if his insulin gets too warm and stops working, and if his pump site fails or gets infected. (Just my little rant to try to get Medtronic to understand why parents want their kids cgm data accessible via Bluetooth and WiFi–because we still need to see the trends!)

I desperately missed the receiver/WiFi readout of dex during his first basketball game! I had no idea what his blood sugars were doing!


while the sensors are accurate, they are not as easy to use as the Dexcom sensors. Yes, they insert way easier than the harpoon sensors we started with and even easier than the G5, but they are still more finicky and not nearly as user friendly as the Dexcom. Pay attention to the arrows! Only calibrate when steady! If you miss a calibration, you get no sensor info. For us the sensors only last 5-6 days instead of the full 7. Yes, Medtronic will replace them for free, if you call and troubleshoot it with them and send it back and spend lots of time on it. BUT it still sucks that my 9 year old has to get a poke every 5 or 6 days when it should stay in 7 (and we frequently got 14 days out of a G5 sensor).

Also it requires 20-40 minutes to charge the transmitter every time you change the sensor, plus a 2-3 hour warm up period. And then guess what! Once you hit the end of the warm up and calibrate…Surprise!! You will have to calibrate again in 6 hours (or loose all cgm data until you do calibrate). So when a sensor fails at night (which is when it usually fails for us) we will be up again between 1 and 4am to calibrate, depending on how early it failed.

Speaking of calibrating…. with Dexcom you calibrate and it instantly updates-like less than 5 seconds!! With the guardian, it takes 1-4 minutes to calibrate!!! It shows you a little bar so you can see how close it is to being done but seriously, 1-4 minutes!

I guess I’m saying that it’s amazing technology but far from perfect, and definitely not a cure. If another pump company came out with a similar system using a Dexcom sensor, I would switch as soon as we could. Unfortunately, Medtronic has the edge (and maybe it just comes down to finding) on the newest technology, so we will continue to change sensors when they die before the 7 days they are supposed to last and suffer through the lack of data and sleepless nights that occurs because he gets kicked out of auto-mode because that’s what T1D parents do, react to bgs or technology as needed, to give our kids the best chance at being in range and healthy.


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