Tandem T-flex

@Eric ask me a while back to post my impressions of my new Tandem T-Flex

I am really enjoying the touchscreen interface of my Tandem pump, I dreaded losing the linked meter I had with my Medtronic but with the touch screen entering BG is effortless, so is entering gram of carbs. This is a much improved way of doing these things.

The larger cartridge of the T-Flex is extremely nice for an insulin resistant T2 like me. My TDD is pretty high, even on days I behave myself, it is nice to be able to go a full three days on a fill.

I have also noticed less irritation of pump sites, can’t explain it, maybe it is the difference in the way the pumping mechanism works. It is not a difference in infusion sets, I’m using the exact same set as before.

One thing I do not like but am getting better at is the fill process. Filling a Tandem is a clunky process with more steps involved. I hope to be an old hand at it after a while.

I am happy with my choice of pumps.


Yes, the fill process is clunky. You do get used to it however. We have been doing it for a year now. It is only a minor annoyance today.

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Also, hoping that the new sets without the luer lock make the bubble issue in the lock go away.


Thanks for sharing the feedback!

I assume this one is connected to Dexcom? Is that now standard with all the Tandem pumps?

Can you tell me how easy it is to do a bolus?

I don’t mean a check-your-BG-and-enter-the-number-and-then-count-the-carbs-and-bolus type of bolus.

I mean, if you wanted to do a specific number of units or fraction of a unit, is there a quick way of doing that? How many button pushes?

Gary, I am assuming you picked the T-flex rather than the T-slim X2 or the T-slim G4 because of the reservoir? Is the reservoir size (and the resulting pump size) the only difference btw the T-flex and the T-slim X2?

@Eric, I think the only one that is connected is the older T-Slim G4.

The T-Flex is an older generation like the T-slim G4. The newer generation is the T-Slim X2. Outside of the software updater (which is important), I have not quite found anything that distinguishes the X2 from the oder generation.

Why the software updater is important: I think only updated pumps will be able to close-loop when it becomes available on the Tandem platform.

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So some Tandem pumps already display Dexcom, but others do not? That’s interesting. I wonder what the rational is there.

Well, it’s all FDA dependent, I imagine. The FDA just approved the X2 with the G5:


So we should expect to see the X2+ G5 combo soon, which means that the T-slim G4 will likely come off the list.

OK, I just figured out something: I had been wondering all along what exactly was the use of the Bluetooth radio in the T-Slim X2. But, in the pipeline page, this is what Tandem says:

the t:slim X2 Insulin Pump […] builds on the original with a variety of improvements including an advanced Bluetooth radio for communication with future technologies.

You have to think that the X2 will be able to communicate with a cellphone. This opens many options similar to the Dana RS.

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Yes, on the Tslim you can over-ride the bolus calculator and just input units (or fractions) at the top of the bolus calculator/input screen.

So to do a bolus, you would unlock the unit (press power, press 1 -2 -3) then press bolus, then click the units number at the tops of the screen and enter the number of units you want. Then confirm request by pressing YES, Then press Deliver.

So the total from not being open is: 6 steps, although the open the device step requires 3 button pushes (1 then 2 then 3)
If the device is already open, it takes one button press to get you to the bolus input/calculator screen shown below. From that screen you can enter units directly, or enter carbs and BG to get a calculation. Once you have done the calculation you can over-ride by pressing the units at the top of the screen and modifying.


Ease of use was one of the primary reasons we picked this one.

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I thought they had a quick button on the side. Is that not correct? Like you have it preset for a dose number, and could just hit it for a bolus. Did I misunderstand that feature?

I don’t ever use the calcs or BG recommendations. I like the idea of taking insulin with the fewest button pushes.

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Yes they have that feature, we just don’t use it.

How come you don’t use it? If you have it set for a small amount, like 0.1 units, would that not be helpful for making an occaisional minor slope correction?

I can do it in 8 button pushes, from a PDM that starts at being off. That’s not horrible, but it’s not great.

Laziness, son isn’t fatigued by the button pressing. Not sure really. I will have to ask him.

We updated our Tandem t:slim X2 with the G5 two weeks ago. I understand the cgm integration is required for the additional updates planned such as the Predictive Low Glucose Suspend (PLGS) and then the Hybrid Closed Loop (HCL). Even still, the G5 integration was somewhat underwhelming. To put it mildly.

As for bolus without looking:
“Setting up the Quick Bolus function enables you to deliver a bolus by simply pressing a button. It is a way to deliver a bolus by following beep/vibration commands without navigating through or viewing the pump screen.”

We do not have the Quick Bolus functionality enabled. It just didn’t seem relevant (at this point) for our needs.


That is surprising to me!

I do 0.1 unit boluses when I need them. Frequently when running, when more insulin would be dangerous. And the sequence of button pushes is not too difficult, but certainly not the easiest task at faster paces.

I would think a quick bolus feature would be very popular, but both yours and Chris’s kids are not using it.

What is even more interesting is that my son does a lot of micro-bolusing based on his CGM readings, so he might actually find it useful.


No it is not, T-Flex is basically their first generation pump with a larger reservoir. It does not connect to a Dexcom and since it is not software update-able it will never be. This was a put off for me at first but I realized that because I have never wished for a CGM it was not a problem. . As a T2 it would be difficult for me to get one.

You are correct, in this instance size does matter.


I’m surprised to hear in this thread that people don’t use the quick bolus button. Do you use it?

I have not although I do have it setup if I wish to use it. Right now I am still trying to dial in my settings on this pump. The limitations of my old pump caused me to run a higher than normal basal rate because I could not set a low enough correction rate. I tried to compensate with an increased basal rate.

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