Reacting to metal infusion set- h

Hi FU people,
I am hoping someone in this wise and smart group will have ideas for me.
My TrueSteel (Tslimx2) infusion sets which are like the Medtronic SureT infusion sets have been failing. (three in a row today!) I use the metal needles because my body doesn’t tolerate the plastic cannula infusion sets. In the days when I used to use them, when I pulled them out there was a little plug in the end of the cannula forming from my body tissue. I have used the metal needles for several years without any difficulty, but lately they have been failing after one or two days or immediately after insertion.
It may be related to my stress level (which has been high lately) or due to scar tissue, since I am slender and don’t have many areas I can use. But my tissue doesn’t feel lumpy or scarred to me…
I might try going back to plastic cannulas and see if I have better luck. Otherwise I will probably need to take a pump break which I am not looking forward to after being on Control IQ.
Any ideas?

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The one thing I can think of is to try one of your infusion sets in some location that has “never” had an infusion set before, to try to get a hint about whether the problem is a general body reaction to this kind of set, or whether it may be an issue only in areas that have been reused.

Another thought is to try changing the kind of insulin (like switching between humalog and novolog) in case there’s something there.

And you could try giving boluses via syringe while reserving the infusion set for control IQ’s basal and corrections: Reducing the amount of insulin that goes into the tissue around the infusion set might help the set last longer.


Steel infusion sets are only meant to be used for 24-48 hours. Check the information that comes in the box of infusion sets, or this Tandem help page:

Set your site reminder for 24–48 hours, then resume insulin.

So I don’t think that having a steel set “only” last for 24-48 hours, without any type of reaction or inflammation visible upon removal, is necessarily abnormal. They aren’t designed to last for 72 hours like cannula sets.

I have reactions to both plastic cannula and steel infusion sets (I have a lot of allergies in general). I change sites daily and, even with that, I sometimes have sites that fail before 24 hours is up. When I remove the infusion set after 24 hours, the site is itchy, red, sore (if pressed), and inflamed. The reaction takes several days to go away.


Thanks for both of your suggestions, bkh and Jen. I have been changing every 2 days, per tandem recommendations, since I got my insurance to approve that about 4 months ago.
I am going to try my leg today and I just got a prescription to try humalog instead of novolog.
Wow, Jen, that must be a real hassle having the site fail so often and getting the reaction at the site. My sites tend look okay after I take the infusion set out. The skin looks fine. Occasionally a site will fail if I get a little bruise under the needle. I do have some other allergies.
I am also working with a somatic therapist to try to see if I can calm my whole body down a little bit.


When we tried the Tandem steel sets, we were able to get three days out of them with no issue. But my son doesn’t have a lot of allergies.

I definitely notice that my body is more reactive to sets if my allergies in general are raging. Sometimes I’ve had to take a short (few days) pump break just to let everything calm down.

I find if I change the site every 24 hours (which I guess I don’t consider an unusual timeframe for the steel sets, since the instructions say to change that often) I react much less than if I try to push it to two days. But generally I’ll watch my blood sugar, and if I have an unusually high high, or if one or two corrections don’t bring a high down, I’ll change out the set. I think people who are able to wear sets beyond 24-48 hours are just lucky to be able to stretch sets, like people who can wear the plastic cannula sets for 4-5 days even though 72 hours is supposed to be the timeframe.

I do worry about scar tissue formation with changing sites so often and especially with sites having so much inflammation. It would be great if I could find a way to prevent the reactions even if I did still have to change every 24 hours.