T-Slim or T-Flex and Occlusion Alert


So, immediately after posting my update and success I started having more occlusion alerts (figures, right?)
This corresponded to moving my infusion site slightly forward to a part of my upper hips that had been used slightly more often in the past. I feel like, at least for me, the likelihood is starting to fall towards my older infusion sites being slightly compromised perhaps with slight lypohypertrophy (although I feel no bumps).
Doing a google scholar search for papers on this it looks like there’s not a whole lot of research but I did find some pearls here and there

I liked this paper in particular:

This may be an example of trying to convince myself that this bad news is actually good news, however It occurs to me that I may have been previously having silent occlusions on my medtronic pump (i.e occlusions that the pump didn’t recognize as such or alert me to) Obviously I’m making a lot of wild guesses here. Hopefully someone smarter than me will make some smarter guesses :wink:


Older thread, but relevant.
I had some alerts early into getting the X2.
After a few months, I finally figured out when I was getting them.
If I put the pump into my pocket, which I do when I get home/off work. I have a higher chance of having an alert…

Now, I use the spibelt ALL the time. I VERY RARELY get an alert if it’s in the spibelt. Maybe a couple since I had it. And I think those were probably real alerts do to my infusion sets having issues.
Every once in a while I will still get an alert if I have the pump in my pocket. But I think that is the only real time.

I am a little different how I fill cartridges. I pull the air out with an empty syringe first. Then I fill my syringe, and pull out more air AGAIN. This second time gets very little actual air, BUT, with a vacuum on the insulin in the syringe, I can tap it against my desk/table a couple times, and it takes out a lot of the entrained air that is suspended in the insulin.
I do all of this pretty quickly. I don’t take super long, and after doing this a few times, I find it works good enough that I don’t really NEED to be all that meticulous to get good results.
To the point that I don’t think any of the alerts are really based on air in my cartridge/infusion set.


I used the Tslim and then Tslim X2 for about a year and a half with no occlusion alerts. Then suddenly I started getting them every 2 or 3 hours. I replaced the nearly full cartridge and everything went back to normal. I suspect the piston was maybe sticking in the cartridge.


I too have had soooo many occlusions from the tslim. I’ve had various pumps over the last 20 years, but this one is by far the worst for me yet. I’ve changed infusion sets 3 times looking for the best one. I thought tru steel was the answer because there could be no kinking in the canula but occlusions have continued and maybe even more frequently. Insulin comes out of the tubing fine, but somewhere between the anchor and needle it gets clogged and sometimes just hours after inserting a new site. One weekend while out of town I had to change sites 5 times in a 6 hour period and when completely out of options, got up and drove home at 3 am. I’m a bit frustrated! I leave for out of the country travel in less than 2 weeks and I want a solution. I’ll be following your thread.


I’m really surprised by the problems you are having with a Tru Steel. I say that because it has been my supposition that the Unomedical Tru Steel is totally identical to their Sure-T with the exception of course, being the connector to the pump–the former being an offshoot of a Luer Lock (T-Lock), and the latter being a proprietary Medtronic connector (which I love, BTW–the connector, I mean).

For years I used cannula sets and eventually I had a rash of occulusions–so many that I nearly quit pumping. As soon as I switched to Sure-T’s the problem went away with just about 1 occlusion occurring every 1 to 2 years apart. That’s several orders of magnitude better than with the Quicksets I used to use. I’d get as many as 2 per week.

Does anyone here have any knowledge of any differences, however minute, that exist between the Tru Steel and the Sure-T, from the disconnect point to the tip of the needle?



Today they decided it’s because I’m not changing my cartridge every other day because I use less than 30 units a day and it holds 300 unit. I change my infusion set every other day though. I can’t imagine that would be the case because I’ve done that for 20 years with various pumps. I hope they’re correct tho. This am the tech said sometimes the needle gets skin in it!!! What? Ya it’s a needle that goes into your skin!!! If my skin is clogging needles I have all kinds of problems. Lol. Anyway, I do like seeing a real steel needle vs Canula for sure. Thank you for your response. I’ll keep following.

May the God of our Lord Jesus Christ, the Father of Glory, that He may grant you a spirit of wisdom and revelation in the deep knowledge of Him,

Jacqueline Bills


I had this problem when I started using the T-Slim, occlusion alarms every day. It was nothing to do with infusion sets or kinked tubing or the site. I would just restart insulin & it carried on happily delivering insulin. It turned out to be something to do with the internal pump temperature. I wasn’t using the pump case supplied with the pump, I found it too difficult to put on. But Tandem support persuaded me to try it. Viola, since then I’ve had no more occlusion alarms,


Jacqueline, you should be able to go at least 3 days on a steel needle set. My wife goes more than 4 or 5, but she and I both use a Medtronic pump. If you were on a Medtronic pump and was using the steel needle (Sure-T), and had issues within 2 days, then I’d conclude that you have some serious scar tissue going on, as that isn’t in the least bit “normal”. I’ve no idea what the occlusion pressure alarm is rated at, compared to a Medtronic. For all I know, it might be more sensitive to back pressure. I’ve never heard anyone quote the ratings or actual-tested back-pressure alarm values.

FYI: her total daily amount is less than yours.


Are u saying it can’t deliver when it gets too warm? That would be a heck of a problem for me and if it happened much, I’d be giving up on that brand.


As soon as I put the pump in the case provided by Tandem the problem stopped. It is not the external pump temperature, but internal temperature. I think this is not a common problem, as I know several people using Tandem pumps who have never had the problem. I wear my pump in a Spibelt close to the skin. The interruption was short, as soon as it alarmed I restarted insulin & it carried on pumping. As it was usually during a bolus I just had to add the insulin that hadn’t been given, the pump tells you how much was given, It didn,t happen for every bolus, maybe once every other day.


Using the Spibelt was what caused the problem, or NOW you use a Spibelt?


No, I used a Spibelt with my Animas pump for years, when I started using the Tandem I carried on using it, when I put the pump in the Tandem case I carried on using the Spibelt. I still think my occlusion problems had nothing to do with how hot the exterior of the pump got. Others live in much hotter climates & don’t have this problem.