Leftover Insulin in Cartridge


I am a new pumper (just started Aug 8). So far I'm very happy to be on the pump. No more injections just about every time I want to eat, and hopefully better control to come. I do have a question for you fellow pumpers though. I apologize if this has been asked 100 times already, but I couldn't find it searching through this forum. Here goes:

Do you reuse the insulin left in your cartridge when it's time to switch out your cartridge and infusion set? Since I just started a few days ago I've only had one set change plus the initial set during training. At my first set change I still had about 40u of insulin left in the cartridge and it's looking like I'll have 20-30 left this time. I did decrease the amount of insulin I put in the second time. According to the trainer you shouldn't put the insulin from the cartridge into another and keep using it, but 20-30 units (certainly 40) is a whole day including basal for me. I know some insulin is rated for a longer life in cartridge than others, but what's the difference between sitting in a cartridge for a few days than sitting in a vial, which the doc tells me is good for 30 days after firs use?

Look forward to hearing the replies!

If you are using a traditional (tubed) pump, there is no reason to change the cartridge when you change your site. I change my site every three days and my cartridge whenever it is very low. Most of the time I get 4 - 5 days per cartridge.


I am on the Animas Ping, so I am tethered. That takes a bit of getting used to in itself, but not too bad.

I try and, time it so I use all the insulin, and yes, I do transfer any leftover insulin to the new cartridge.

I have an Animas Ping, and I have found that I can figure out about how much insulin I need for a three day infusion set change. If there is a few units left, I transfer it back into the vial and use it again. I have had no issues.

I know this isn't recommended policy, but I am not a wasteful person, and I hate to see that insulin go down to waste. I probably would be cautious if the insulin in the pump had become exceedingly hot for any reason, or had frozen. I have experienced neither. I use Apidra, and have heard that isn't the best hot weather insulin. I have had no problems with it.

Is there any reason you transfer the insulin from the old cartridge to a new one rather than just letting it run out whenever it runs out?

You'll be surprised how quickly you adjust to being tethered! I use the 43" tubing. You would think that would be too much tubing, (especially for a woman), but what it does is allows me to put the pump down when I'm getting dressed for example and without feeling it pulling on me I don't feel as "tethered" as I did with the shorter tubing.

Wouldn't it just be easier to leave your infusion set on one more day?? That way you use all of your insulin and there is no waste.

I leave my medtronic sets in four to 4 1/2 days. Since I have been pumping a long time, I can pretty accurately fill the cartridge to leave 20 units or so in the cartridge when I switch out.

I do not reuse the insulin or the cartridge. I just feel safer with new insulin. The stuff in the cartridge has been in a high temp environment (my pocket, bra, etc.)

for all that time.

I change my infusion set every two to three days or anytime I seem to be having some set fade. I change my reservoir when it's low....under 10u.

I would also add that your insulin Rx should include a extra 25% for tube filling and other issues.

As long as my absorption is good and the site isn't falling out, I will leave my set in up to 4 or 5 days. I also do reuse both the reservoir and insulin, but only one time. I believe humalog can technically survive in a reservoir for 6 days, and the only time I've noticed any issues with efficacy is during the really hot summer months when I've spent a lot of time outdoors. Personally, I feel like pumps create a lot of waste, and if there's something that I can do to help cut down on that waste without jeopardizing my health, I'll do it.

I agree, if my site and cartridge changes don't line up, I'll change the site and then just use the same cartridge for another few hours or half a day until it runs out before changing it. I rarely change with more than 5u left in the cartridge.

I agree with what others have said. I use the Animas Ping, too. So you can do a few things: Only fill the cartridge enough to last you 2-3 days (or however long you've been instructed to change your infusion set). Or, you can just change the infusion set but keep using the same cartridge until it runs out. Or, you can just wear the whole thing a little longer as long as your site is still absorbing the insulin and your site is not getting infected. I usually change my set about every 2.5 days, but I end up using up pretty much the whole cartridge by that time, so if there is ever any insulin left, it's usually only about 5 units.

ok, so I have a question. The longer you keep your infusion site in one place, this means that absorption can minimize? I am so new to this that I have no clue on the what you should or should not do. I have been changing every 3 days. I let it go for 4 days once because I had alot of insulin left and my site was red after taking it off. Took a few days for the redness to go away. So I have been diligently changing every 3 days.

I try to estimate how much insulin I will require for 3 days. I put about 130 to 140 units in my cartridge. When I change out 3 days later, I'm usually under 30 units. I'll toss the cartridge, waste the insulin and start over with fresh cartridge, fresh insulin, new site, the whole works.

I have 80% coverage for insulin, so I'm only paying under $9 a bottle. My other supplies, I am fortunate to have 100% coverage. With this in mind, I'd rather be safe and start fresh every 3 days.

As a new pumper, I have noticed more itching around the infusion point after some 72 hours. If I change sites at this time I sometimes notice higher Blood Glocuse numbers for the same amount of carbs.. Most of the time, if the itching is a higher level, my infusion tube is 45 to 90 bent near the end of the insulin infusion delivery point. In talking with Medtronic's customer support, they tell me to stand up, and only lightly lay the infusion easy setter against my infusion point. They have replaced the bent infusion sets after my calls. Any body else had this problem?

I discard the leftover insulin, but I try to only add enough for 3 days. My situation may be a bit different than others because I am very sensitive to insulin. (Basal and bolus total 16 units per day.) 1 insulin vial always lasts 28 days.

I change my site every 2-3 days my resvoir usually lasts for 3-4 days. If I have too little insulin left in a resvoir when I'm ready to eat I fill another resvoir and get the little bit of insulin out of the old one with a syringe. I have MM 522.

My daughter pumps with an animas 2020. We used to waste insulin in the manner you write of until I realized that the cartridge change date and the infusion set change date don't have to be the same. Now we change the infusion set every 3 days and save the new tubing until the next cartridge change is needed due to low insulin. Tends to be a 4 day schedule of changing the cartridge/tubing so this will occasionally line up with an infusion set change. Anyway, we waste much less insulin now and it's easier to fill the new cartridge completely full rather than to an estimated amount based on 3 days. Plus, if you have a bad site, you don't have to throw away a bunch of insulin. Hope that helps.