T:Slim X2 vs. Medtronic 670g

Interesting you mention the calibrating on your 670G. Medtronic’s tech support advises a minimum of 4 time a day, at least the last one I spoke with did so. I have been on this pump for two years and I am really disappointed in its performance. Calling the 670G needy, as one commenter called it, is absolutely true. It has ruined many a nights sleep. I am here to gather information from Tandem users as I consider my next pump purchase.

You’ve probably already read through the responses so I will just highlight some people do complain about the relative fill process. I switched from Minimed (Medtronic) to Tandem many years ago and am used to it, but this who make the switch tend to complain that the prices takes longer, and there is a certain amount of insulin that goes to waste. A tip for speeding up the fill: when I get a new bottle of insulin I fill several cartridges at once and keep them in a covered container (I put them in the fridge) so they’re ready when it’s time for a site change.
If you have concerns about charging it rather than using batteries, I plug mine in when I’m taking a shower, sitting watching TV, or even while I’m driving. And I keep one of those “charging bricks” for my phone, so if I need to move around while charging that works well. I find it charges quickly.
I believe Tandem has an interactive tool you can use online to check out some of the functions.

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I have been on the 670G for two years. It is truly a challenge to keep it from driving you nuts with all of its requests for attention. I am on this forum to learn more about the Tandem and I am very close to making the switch The Dexcom G6 CGM is superior to the Medtronic Guardian which requires four calibrations per day per their tech support. The pump still requests additional BG readings randomly even when a calibration is not needed. That random request at 2:00am will give you a new perspective on Medtronic.


I would like to share my experience as a former Medtronic 670g user who has been using the Tandem t:slim with Control IQ for the past 8 months. Patients’ subjective impressions are important, but I’ve noticed a lack of quantitative data in most patients’ stories. I have both.

I’ve been a pump user for about 25 years, almost all of them on Minimed/Medtronic pumps. I was generally satisfied with my pumps until Medtronic introduced integrated CGM. Medtronic has gradually improved its buggy and inaccurate CGM equipment, but even the latest Enlite iteration required many calibrations a day and was inaccurate enough that I would usually turn it off at night so I could sleep. Meanwhile, the 670G’s supposed breakthrough feature, the automatic adjusting basal rate, was accompanied by so many irritating safety features that I found myself paying way more attention to my pump than I cared to. At the same time, the algorithm was so conservative that I found my overall blood-glucose level was being maintained (albeit poorly) at a higher level than I was able to do by my own devices.

Previous to the 670G, my A1Cs generally fluctuated between 7.6 and 7.8. After four months on the 670G, I registered my first-ever A1C of 8.0. My glycemic control was actually getting worse, not better. The folks at Medtronic told me that the main goal is to keep me from having dangerous lows and highs, not necessarily overall better A1Cs, but the faulty CGM was contributing to wide swings in blood sugar while the over-cautious algorithm was keeping the baseline average at a level of poor glycemic control.

My endocrinologist had been trying to get me to try the Tandem pump with the Dexcom CGM for the past couple years, telling me that switching had helped a number of her other patients achieve better control. and showed me how After four months of the 670g, and having heard of the $1000 rental program at Tandem, I decided to finally take the plunge.

It took me almost three months to effect the switch (one thing I will say for Medtronic is that their marketing, sales and fulfillment operations are leagues ahead of Tandem’s and Dexcom’s). However, once I started on the t:slim with Control IQ and the Dexcom CGM, I experienced immediate benefits. Virtually no finger-prick BG testing, super-accurate CGM readings, and a pump that only bothers you when you need to be bothered, including almost no interrupted sleep ever.

The best thing about my new gear, though, is my improved glycemic control. My next A1C, four months after switching, was only 6.7 – the best in my life and 1.3 lower than my last result with the 670g. And my most recent result, another four months later, was 6.5. This was after practically no lifestyle changes – just different equipment.

At this point in time, Tandem and Dexcom simply have the better products. I think it’s possible that Medtronic, with its huge resources, can catch up. Ironically, I think Tandem benefited from being second, not first, to seek approval for its basal-adjustment algorithm. I suspect that Medtronic’s next iteration will be much less conservative, but in order to do that, they will need a much more accurate CGM. The obvious course of action is to kill their own CGM program and hitch their wagon, as Tandem did, to Dexcom. Using the Dexcom CGM and a better basal algorithm, along with less nervous-Nellie safety programming, and Medtronic would have something akin to what I’m enjoying now with the t:slim and G6. I hope they make those improvements; all diabetic pumpers would benefit from healthy competition.