Infusion Set Cannula Length

Some extremely smart person on this forum must know how to select the best cannula length. Sets come in 6mm, 9mm, 13mm, 17 mm, etc. Why would a person prefer a shorter vs longer cannula length?

Thanks in advance for sharing your knowledge!

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Need to also consider if set is 90 degree (straight in) or inserted at an angle. I use the shorter 6mm with straight in 90 degree (quick set). An angled 13-17mm can be 30-90 degree insertion, mostly used as shallow/low angle) for those that use them.


Same. 90 degree 6 mm.


Thanks for the replies @MM2 and @Thomas! I have been using 90° sets with a 6mm cannula too, in addition to 30° 13mm sets. What advantage if any would there be to a 9mm cannula on a 90° set and a 17mm cannula on a 30° set? I am attempting to ascertain if I am using the correct length cannulas.

These would help in areas with thicker skin or fatty areas. The 30 can be angled upon insertion to be deep or shallow. I think @daisymae mentioned using them because 6mm straight in was too deep/painful. She may be using 20-25 degree angle.

Many years ago, before quicksets, I used the angled sets, but so happy when they come out with quick-sets.

Tried the steel sets, but did not like at all.


that’s exactly why and how I do it. 20/25 degree angle, barely under the skin. I got no fat in my tummy.


If your 6mm sets seem to have inconsistent absorption/insulin action, the 9 mm can be option to see if it improves. You should be able to get samples from endo or pump company.


@MM2 , @daisymae and @Thomas, I very much appreciate your help. I have an Endo appt next week with a new Endo. I hoping she won’t think I’m a complete idiot for asking about longer cannulas. Depending on location, I do have absorption issues.

Thanks again for all the help!


I use the 6mm @elver because I have a relatively low BMI. The 9mm used to work fine, but that was 40 lbs ago


I have used most of those. In theory the longer ones are more likely to stay inserted if you pull the tubing hard enough or sweat hard enough to partially dislodge the patch. That can help for little while, but in fact I usually have to replace eventually in that situation, and the shorter ones do less tissue damage. I am currently using up the last of my old 10mm Accu-Chek Ultraflex sets, and that length was ideal for me with a 90 degree straight in. Tandem doesn’t sell them, so I will have to change.

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Thanks for the info @Randy and @Jim_YYC ! II greatly appreciate it. :slightly_smiling_face:

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Hope I did not miss your endo appointment!

So much of it comes down to absorption speed, comfort, consistency, and longevity. And each person is different, because of variations in tissue, body type, activity, and amount of insulin they use, etc.

So while you may get a recommendation from an endo, or someone who uses one size and it works perfectly for them, the best way to do this is to try different types and pick what works best for you.

Ideally, you could get a script for all the different infusion sets that are available for your pump, and just get a different one for a month, try it out, move on the to next one. Over time you will be able to conclude which set gives you the best results for your individual circumstances.

I know this seems simplistic. But as an analogy - what if I told you how much I bolus for a large pizza. You wouldn’t necessarily do the same thing.

Along the same lines, if I tell you what infusion set would work best for me, it’s very much like telling you how much I bolus for pizza. It can be very different.

I strongly encourage you to pursue trying various ones. There is no better way to know. And those should be interchangeable for insurance. If you have a script for one, try it out, and then try the next, etc.

Do you think your endo would do that for you?


@Eric I am fortunate in that my Endo wrote the original RX as patient preference, so I have been trying various sets over the last few years. I’m down to 2 styles and have not seen any discernible difference in efficacy utilizing one cannula length over another which prompted my ask. My Endo suggested I ask my CDE or Tandem. Tandem said I should ask my Dr, and my CDE said it was patient preference and it it ain’t broke, don’t fix it. So I promptly asked where I knew I would actually get some guidance with validated information - FUD.

Thanks for the info @Eric! FUD is my go-to resource when I am well and truly stumped. :face_with_monocle:

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I am sorry, I didn’t know you had already tried them all.

That’s cool that you already did that. So you are way ahead of my post. Sorry, I may have missed it.

Great that you got the script written that way too.


Of course, it’s the best place to go for that.

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I haven’t tried them all…yet…I’m still a work in progress but didn’t understand the longer cannula length benefits and have yet to try them. Now I will.

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tried the steel sets when I was first starting out on the pump. very long and very painful. and very scary; dreaded having to change them out.

then I saw a pregnant woman at work and she had the quick set. it was so tiny and looked so comfortable. I called my endo immediately and had my prescription changed. it wasn’t till later on that my CDE mentioned using a shorter cannula bc I was so skinny and was having problems with scaring. then Eric suggested to me to try changing my sites out every other day (as opposed to every 3rd day) and the scaring went away and my absorption was infinitely improved. also, without having to deal with scaring, it became more comfortable changing out my sets. but my BYDMV.

like everyone else suggested: you just need to try them out and see which one is most comfortable and helpful for you.

also, as a post script: I used to have a LOT of bleeders, but since I switched to the shorter cannula I rarely get them any more.


Hey DM, was meaning to ask you today, how are you doing? Are you feeling better?

I hope you were able to get into the city today, and hope you are feeling better. The pool is calling you!


funny, but I just posted on my swim thread. Bobby wouldn’t let me go out today due to miserable weather and his fear (and a little of mine) that I would have a rebound virus till I felt 100%.

I am soooo stir crazy that its just killing me. tomorrow I will definitely get out. I need to pop into the City for an errand, and I have to get my blood drawn 'cause I am seeing my endo next week (nov 20th). I don’t even want to think about how this has effected my A1c (although despite being sick, my BGs have been under tight control due to setting TBs and changing ICRs to match my bolus insulin needs. once Bobby took my temp (130), I realized why I was having such a difficult time with my BGs. then I changed everything, and ever since my BGs haven’t gone over 110. basically staying in the 80s.


thanks for asking :heart:


Oh, yeah! Are those still working for you?

Are you running the higher one now since you have been sick?

Keep in mind, I can give you updates easily, just ask!

I hope you are at home on Friday…


what happens on Friday?

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