Tandem T:Slim X2 unnecessary restrictions!


Good Day all, I am posting this to enlighten users of the Tandem X2 insulin pump who may not know it and hope that Tandem sends out an update to change it.
I have just begun using the X2 about three days now and while at work I ran out of novolg insulin. I had insulin in my vial which had about 65 units in it which was more than enough.
After loading the pump cartridge it notified me that I had less than 50 units and the pump requires more than 50 units. WTF! I just finished eating, my glucose is rising pass 300mg and my new pump which has insulin in it will not let me use it! This restriction forced me to leave work after two hours but the situation could have been worse like traveling out of state.
This issue needs to be addressed by Tandem as being a former ANIMAS pump user I could load up any amount I needed to treat my condition if in a pinch.
Of course if I had known this I would have taken two vials to work with me.
Anybody using the Tandem T:Slim X2 give them a call and complain about this unnecessary restriction to get them to send out an update. Thanks.


@Robert14 If i understand your post correctly you had +50 units in the reservoir after priming, etc. and you were unable to access the insulin?

  • If this value (the 50 units) was pre-priming, that is most likely your issue as Tandem thinks you need +45 units prior to use. That was most likely the case before the T:Lock was introduced, but is not currently accurate.
  • If this was post priming is there a setting that needs to be adjusted? I routinely run my reservoir to zero on day 3 or 4. When I attempt to extract any remaining insulin from the used reservoir I generally get <4 units.


As @El_Ver mentions, with a regular syringe, the insulin can be extracted. This is a great backup which covers any number of situations where the pump is (for whatever reason whether pump, infusion site, battery, etc…) unable to properly deliver a dose.


El_ver good day, just to clear it up I withdrew 65 units from my Novolog insulin vial and loaded it in the Tandem cartridge. After priming, the Tandem X2 pump notified me that the pump will not deliver insulin if it is less than 50 units upon loading it up for use.


How many units did you use in the priming?

With 23" tubing and the t:lock and not priming more than required, this would typically have been enough. But with very very little to spare.

If using the Luer Lock or longer tubing or simply being a little slow on the stopping of the priming, it would have been very easy to end up on the short side.

However with a syringe available as a backup, the insulin could have been extracted from the cartridge and injected as normal bolus as appropriate.


@Tim35, @Robert14 if I am understanding the issue correctly, the problem lies with the FIRST bolus after priming and the pump thinking there is insufficient insulin to bolus. Were it me, I would do a “Load cartridge” on the pump, add 10-15 units of Humalog/Novolog to the reservoir, and re-insert as a “new” cartridge. Then skip all the priming steps and set reminders. That way you can add a small amount of insulin to an existing reservoir and possibly “fool” the system by making it above an unmentioned threshold.


I have never tried as you describe but just wondering if it is possible to skip the priming steps? I thought the priming was required (as part of a cartridge change) and for the priming step, 10 units is the minimum for priming?


@Tim35, I prime about 12 units give or take 1 unit or 2. That fills the tubing when I see the drops. In the initial incident I should have had at least 50 units give or take after priming. The bottom line is the Tandem X2 insulin pump should not prohibit delivery of insulin if you have less than 50 units after priming. I could give numerous examples of having just enough insulin in the vial put it in my ANIMAS pump and use it. I dread having to go back to using the needle for a bolus.


Are you sure about the 50 units? That’s my confusion here, because my pump just told me a few days ago that it needed at least 40. Maybe this is a software change?

Tandem claims that there is about 15 units of inaccessible insulin in a cartridge, but it my experience it’s been more like twenty Plus it takes 11-14 units to prime 23 inch tubing. If you were even just a few units shy of the 65 units you think you put in it, that would’ve put you out of functional range.

It sucks, but I think it’s just one of those growing pains you’ll get used to after a little longer with your new pump. I think we all agree that no pump is perfect yet. I love my X2, but I do have three complaints about it. That 20 inaccessible units is one of them. (As a new pumper, the insulin lost to the tubing was irksome, too, but unavoidable.) The minimum fill requirement is NOT a complaint for me. 40 units is approximately my total daily dose, so I’d never need to fill anything remotely close to less than that.

I’m sorry you had a bad experience with Tandem, though. I will tell you that they are VERY receptive to feedback. When I called about my first complaint, I was put through to two different levels of management and within a few days a member of the design team spent nearly three hours in the phone with me brainstorming about my complaint. I was really impressed with that. So by all means, if you feel strongly about this, contact them and work with them to find a better solution. Just be aware that this may be one of those unavoidable FDA requirements. I can’t see any reason why they would voluntarily set a minimum.


@Tim35 I add small amounts of insulin to an in-service reservoir and skip the priming regularly


I should have better explained that as, your pump won’t even register 15-20 units. They just disappear. I’m not about to waste half a days worth of insulin, though, so I suck it back out with the syringe and add it to the fill volume of the next cartridge. Some wouldn’t agree with that since insulin does degrade over time and faster with body heat, but I’ve found the difference to be completely negligible.


I also have had this problem with my x2… is there any way to reduce the minimum amount the pump needs after priming to function? I use only 40 units for the entire three day span and often have issues with the priming process because of the 50 u minimum.


Good to know !!!


@bubblywhale you could fill more than you need for the 3 days and pull out the balance on the next change… Alternatively you could run the reservoir longer and just change the set. I understand the concern that many people have regarding degradation of the insulin. Maybe I have been lucky, but I have never experienced this (yet). I am also a thrifty (read: cheap) person and use things as long as possible to backstock a rainy day supply.


Hi Robert. The Tandem does not allow less than 59 units of insulin. It will give the same error message the gentleman was speaking about


Thank you Antoinette