Returning Tslim insulin pump

I am starting the process of returning the Tslim. The measurements of .1 unit made it very difficult for me to understand how much insulin I was actually getting. I have been on the Animas pumps prior to my Medtronic 630 and the measurements have always been on the quarter. .275, .300 and so on. I don’t believe I could manage my basal rate adjustments with the tslim. I can always look forward to medtronic’s 780. Hopefully that won’t be too far away.

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Sorry it didn’t work out for you.

I’m surprised that tandem has this limitation, especially when it has micro-delivery increments .001. Not supporting basal segment < .100 is likely carry over from previous pumps, and low demand for that feature.

Good luck.

Yeah, I didn’t realize the basal segments were different when I got interested in this pump. My last 3 pumps were all on the 1/4 segments. If I could have understood how much insulin is .1 I might have been okay. I can understand 1/4 of a unit but not .001. Tandem says that they can deliver that small of a basal rate but you have to do it with an series of zero insulin on the 15 minute mark. The Tandem rep wrote out a basal program for me below. This looks very confusing and a nightmare to make adjustments. I have rates such as .025 and .075. The T tandem pump won’t do that. You practically have to be a mathemetician in order to figure that out. I guess I have to stick with Medtronic pumps. Hey, that’s not so bad.Just as long as they come out with the 780. I will cry tears of joy!:rofl:
12am Basal - 0.1
2:30am Basal 0

5:00 am Basal 0.175

9:00 am Basal 0.1

11:30 am Basal 0

1:00 pm Basal 0.1

3:00 pm Basal 0.125

9:00pm Basal 0.1

9:15 pm Basal 0

10:00pm Basal 0.1

10:15pm Basal 0

11:00pm Basal 0.1

11:15 pm Basal 0

Glad you worked with tandem, hopefully they will feedback to team that would fix this in future. Since tslim is updatable, may be not to far in future. And since Medtronic can support, and tandem loses business, makes sense for them to address.

Good luck.

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Yes, good point! I don’t know how many other people are like me, but I can understand 1/4, 1/2, 3/4, and 1. You practically have to be a mathematician in order to figure out what a basal of .025. To tell you the truth, I was becoming a little annoyed with having to tap 1, 2, 3, in order to unlock the pump each time. If your fingers got clumsy and tapped the screen 3 times and missed the button you were tapping the screen would lock. So you had to press 1, 2, 3, again!! Just as well. The Medtronic pump is easy to change the cartridge, fiasp works well in it. No occlusions. No l pig tail in the tubing. I’m okay with it. Medtronic is supposed to be coming out with the 780. Good things come to those who wait.:slightly_smiling_face:

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Looks like Europe may be getting 780 soon.

Here is excerpt

The 780G is one in a new line of Medtronic insulin pumps with Bluetooth smartphone connectivity. Also CE-marked are the Minimed 770G2 system, which comprises the same hybrid closed-loop technology as the 670G system, and the 770G3, which provides users with readings from a Medtronic glucose sensor without triggering an automatic insulin dose based on those readings. Rollout of those systems will depend on individual market approvals, the company said.

I read somewhere that a later MM pump would be integrated with Dexcom cgms, but don’t know timeline.

I’m glad you get a solid return policy. This is a bit tricky. To be perfectly honest, I have a degree in math and I really had to look at it. It’s not very intuitive.

1/4 = 0.25 = 25%
1/2 = 0.50 = 50%
1/10 = 0.10 = 10%
1/100 = 0.010 = 1%
1/1,000 = 0.0010 = 0.1%

It’s good you discovered this flaw. Now, we can warn others. Goes to show that you never know until you try in medical devices and in cooking.

I feel bad that we didn’t think up a way to simplify the math for you. I’ve had it in the back of my head and was thinking about what type of computer program I could write to help. But, in all honesty, if you gotta write a computer program, there’s a problem. Diluted insulin would have been the way to go to increase ease of use. Diluted insulin is simpler than math.

Dee - The explorer of uncharted insulin pump territory. Going where none of us have gone before…into the world of terrible, unintelligible arithmetic. I’m sorry this didn’t work out for you. It seems you have pretty limited options. I respect your bold, honest exploration. Your criticism is super valid. Strange that no one else has bumped into this before.

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The way to think about your dosing would have this:
Most of the time, when we talk about basal rates, we are talking about an amount of insulin that is delivered over the course of an hour. But, when we talk about your dose, its only being delivered over 15 min, so its 1/4 of the amount of insulin (15 min is 1/4 of an hour).

Typically, A basal rate of 1 means that we deliver 1 unit over 1 hour. A basal rate of 2 means that we deliver 2 units over an hour.

You were delivering insulin over a much shorter time period - a quarter of an hour (1/4 of an hour).

So, instead of delivering 0.1 units per hour, you delivered 0.1 x (25%) = 0.1 x 0.25 = 0.025 units per quarter of an hour (15 minutes). So, you have to divide the dose by 4 to make it the same as how we usually talk about it.

There are 4 quarters in a dollar. You were only delivering a quarters worth of insulin.

So, 0.1/4 = 0.025

0.025 is 1/4 of 0.1

If, instead, you delivered that same dose (0.1 units) over 30 min, or 1/2 an hour, then
you would need to divide 0.1 units by 2.
0.1/2 = 0.05 units
Twice as much time = twice as much insulin.

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I read that too. Medtronic is going to partner with tidepool. They are going to add bluetooth so that users can select the system that works for them. Medtronic realizes that people were having insurance problems because Medicare didn’t cover Medtronic’s sensors. It put those people at a disavantage. They also realize that their 670 system wasn’t cracked up to what it is supposed to be. It needed 3 or 4 fingerstick calibrations for the sensor to be accurate. It locked people out of automode, The new pump will also have an adjustable target and automatic corrections if carbohydrates weren’t calculated properly. Sounds very promising indeed. I think medtronic realizes that they can’t compete with dexcom because that is all dexcom does is cgms. In my government program they say I won’t become eligible for a new pump until 2022. They are going from when my vibe got replaced by my 630. It should have been in 2021. Oh well, by that time maybe the 780 will be available.

I really appreciate your heartfelt reply but to tell you the truth I felt so much safer on my medtronic when I connected to it on Sunday after supper. Tandem was saying that “we have the insulin pump with the smallest basal rate.” Turns out the only way to achieve that is with a series of starts and stops at certain intervals. It may be “pretty slim” but I have to do what works for me and medtronic’s pumps do that.


I totally get it.

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The dexcom G7 will be similar to FS Libre, and Libre also getting into iCGM classification. Will be interesting if they become truly mix and match and more cost competitive.

Her normal dose using Medtronic pump is delivered over hour.

The issue is that tslim pump requires a minimum .100 data entry per segment basal rate.
It allows .101, allowing .001 precision above .100.
To mimic what Medtronic pump can do, she was using 0 segments + .100 segment. Her total basal is unusually low.

She gave it a good try, but its fault of pump to not allow segment less than .100, when the micro-delivery can deliver .001 per pulse.


Yea, that’s an unlucky break. Thanks for clarifying. I feel bad that this happened to her.

I think people are splitting hairs here. Who has a basal rate less than 0.1 per hour? For a person whose basal is only a mere 20% of their daily dose, that’s a total daily dose of only 7 units per day. That’s incredibly unusual. And, as was pointed out, you could alternate with a basal of 0 for short periods of time to achieve a lower effective rate. Furthermore, I seriously doubt a Medtronic pump could accurately or reliably deliver a dose so small.

As far as converting fractions to decimals is concerned, get a calculator. Enter a 1. Divide by 4. There, you have your entree for 1/4th.

The bottom line is which pump results in better control. And frankly, you need a pump that integrates with an accurate and reliable sensor for that. Medtronic doesn’t; Tandem does.


I am now thinking about getting the 770. The cgm will get more accurate and easier to insert and no calibrations needed except on the first day. I do that with my dexcom, no big deal. I like the idea of software updates, that way I won’t have to wait 5 years under my province program. I wasn’t supposed to get a new pump until 2023. If I jump on this I will get it 2 years earlier.:slightly_smiling_face::+1::scream_cat: