Frequent Occlusions with Tandem X2

A few months ago my son switched from a Medtronic pump to Tandem X2. Since the switch he is getting an occlusion alarm several times a week. Does anyone know what might be causing this?

He’s been pumping for 8 years and also has used Dexcom for 5 years. The only thing new is the Tandem pump.

What infusion sets are he using?

The Tandem infusion set is AutoSoft XC. It looks the same as the Medtronic Mio that he used for many years without any problems.

@Yifat. Double check to make sure the air vents in the back of the pump are not blocked.

Are there certain sets that have this occlusion problem?

I’ve had this pump for a year and only have had 1-2 occlusion issues ever. I wonder if some people get occlusion alarms if they did not follow the instructions for setting it up correctly? Does he do every step as directed?

What insulin is he using? Apidra is a known problem. It crystalizes in the pump. A few have had issues with fiasp, too. Some people are lucky with it, though. I can’t remember if it was big or small boluses that were working fine.

I have issues using Fiasp when shorter cannula, or angled ones.
I can also have issues with Fiasp when I wear my set for longer than 3 days.

Also, the Tandem pump has a different way it pump the insulin that makes it far more accurate, but also means it can have other issues for some people.

I have used a Tandem X2 for 3 years and have never been able to eliminate occlusion alarms. Fortunately I only get about 1 per week and all I have to do is Resume Insulin. I am on my 4th pump and interestingly, one never had a single occlusion alarm but had to be replaced for a defective T-button. Most of mine happen when the cartridge has about 80-120 units in it.

I believe that there are things to do to reduce the number of occlusion alarms. But I also believe that it is some sort of air or pressure sensor that is defective in some pumps. I get very tired of people who don’t get occlusion alarms thinking that those of us who do are doing something wrong.

I no longer carry my pump in my pocket although that’s how I prefer to carry it. I use TruSteel sets and get occlusion alarms as frequently with those sets as VariSoft sets. One thing that might help is their case but I won’t use it. Another thing I do that is “wrong” is use my cartridges for longer than 3 days. But my occlusions sometimes happen on the second day so they wouldn’t be eliminated by a 3-day change.

I have given up on troubleshooting with Tandem. Most of my alarms happen during boluses but not all. I had one in the middle of the night recently and then quite inconveniently during yoga class and at the movies. I never had an occlusion alarm in 12 years of pumping with Medtronic and Animas so consider this to be a Tandem problem.

Things that might help: 1) Do not carry pump in pocket, 2) Use TruSteel infusion sets, 3) Use Tandem case, 4) Hold tubing out straight during boluses, 5) Don’t use Apidra, 6) Work with your local Tandem rep or trainer and insist on a new pump. Some people are helped by a replacement pump, but I wasn’t. Frankly you get refurbished pumps and you may just get a pump that someone else returned due to occlusion alarms.

In 3 years I have only had 1 day that finally required a cartridge and infusion set change. The rest have all been false. Totally annoying and I have slowly come to accept them because I unfortunately have no choice. I would never switch to Medtronic because I am a committed Dexcom user. And my skin and tissue can’t tolerate Omnipod. And fortunately I mostly like my Tandem pump.


The technology used. It’s nothing like Medtronic’s, which is quite robust.

Thanks for your explanation.

I have been trying to wait for Tandem to announce their Total IQ pump, before abandoning my ancient 522/722 MDT pumps, but I might keep hanging on and wait for either Bigfoot or the iLet to arrive.

I’ve had my X2 for two years now and haven’t had any more occlusion alarms than I had with my Animas or Disetronic pumps over the last 20+years. I was using Autosoft 90 (6mm) sets or the equivalent Animas version. I was using steel cannula infusion sets on the Disetronic pumps.

The only other thing to add is that the past month I’ve been using the TruSteel infusion sets (6mm) and I had two occlusion alarms. I haven’t been using them long enough to conclude the two are related.

The pumping mechanism is indeed different. Maybe something to do with cannula length and your son’s body tissue that has an impact? Shear speculation.

I understand it didn’t help, but what has Tandem TCS suggested so far?

I find the local Tandem rep has more comprehensive knowledge than the phone TCS.

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My X2 goes out of warranty in December 2020, a year from now. Given the choices on the market today, I would choose Tandem again. Since I am on Medicare, I have no idea how quickly I will get access to Bigfoot or iLet. Plus since Bigfoot has gone with the Freestyle Libre instead of Dexcom, I am not sure that I want to take the risk to switch. Whatever… I know that I live with #firstworldprivilege and am not losing sleep over my next pump choice.

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Thanks again, I keep forgetting the Medicare hurdle(s)!

I’m in the same boat …

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I could be wrong, but it was my understanding that the X2 would be able to be updated with that software once they have it available. I very well could’ve made this up in my head, but I remember talking with a tandem rep and she told me that any new software that comes out can be installed on the X2.

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That’s correct. I updated to Basal-IQ when it was released and I will probably upgrade to Control-IQ when it’s available (hopefully soon). My Tandem rep also told me recently they are working on a way to go back to previous versions if you don’t like the new version for some reason. Right now it’s one-way only.

At one of the recent Tandem earnings calls the CEO said they planned on releasing new software versions for the X2 every year or so. One of the X2’s big advantages is it can be updated so when something new comes out that is compatible with the pump’s hardware, you can upgrade instead of buying a new pump.