Looking to upgrade from 640G, thinking of Tslim

So basically the title of this topic!

I’ve lived with T1D for 15 years now, have been on the pump for around 10 of those.
I’ve been using my 640G and haven’t had any problems with it, but with my renewal period coming, I’m hoping to upgrade.

The new release of the 770G from medtronic is interesting to me, since it can automatically change delivery of insulin depending on what your CGM monitor is detecting ( less insulin if low, more if high, etc)

However I have noticed that the T-slim X2 can do the same if using the Dexcom G6 CGM device.

With all of that out of the way, I have the following questions.

  • Has anyone moved from the Medtronic pumps to the Tslim X2, and what has your experience been?
  • In Australia, are the Dexcom G6 CGM supplies covered by NDSS/Medicare, or will I be out of pocket?
    -Can the Dexcom G5 sensors worth with the Tslim X2, and can I still use the Control IQ function with the G5 sensors?

Apologies for the terrible formatting and the rambling in this post!

Hi @NicholasD. I can help with one part of your question: you can use your X2 as the receiver for Dexcom’s G5, but you must use the G6 sensors for CIQ (and BIQ). BIQ and CIQ both features require upgrades to the pump and you can’t go back to the G5 once that’s done. At least that’s how it is in the US.
No need to apologize for anything - ask what you need.


Nicholas @NicholasD, moving from 640G to 770G, or from 640G to Tandem x2 is more of paradigm shift than a simple “pump upgrade” if you are considering moving to AIDs [automatic insulin dosing system]. An important point, and response to your questions:

  • If you will stay with Medtronic/MiniMed insulin pumps, consider waiting for release of the 780G; the 780G is designed to be comparable with the Tandem t-Slim x2/DexCom G6 system. The 770G is a lower class system.
  • I used three different MiniMed/Medtronic model pumps before changing to Tandem t-Slim. Tandem was, for me, far superiors to any MiniMed. Currently I use the Control IQ Algorithm with my t-Slim G6 system, which is the inly iAIDs approved device; this system provides me with almost “hands-off” diabetes management with TIR in mid-90% range - not bad for an 80 year-old who has had diabetes since the 1950’s ;
  • I don’t know anything about your insurance coverage. In the USA, Medicare covers my pump supplies, my CGM supplies, at 100% - I get three months supply shipments at no cost to me. I did have to make a couple of hundred dollar co-pay for my Tandem pump.
  • Tandem t-Slim will NOT connect with DexCom G5. Older t-Slim pumps connected with the G5 - my t-Slim manufactured in 2018 was too “advanced” to connect with G5.
  • Control IQ will [currently] operate only with the Tandem t-Slim x2, combined with DexCom G6 sensor

If you are considering the Control IQ method, or the projected Medtronic 780G system, you will need to trust your equipment, and avoid second-guessing.

Interesting that the newer versions wont work with the Dexcom G5, if that’s the case I wouldn’t be able to use any CGM until my government decides to subsidize it!