FDA approves Tandem Basal-IQ

I upgraded my X2, now just waiting for the VA to push through the G6 order, should be another month, or 5…


Basal-IQ is great. But it is not magic and only knows what it knows. It does not know about food.

We are very new to this only being three days in.

So tonight we had a straight and level BG right at 80 going into dinner. Pizza.
(OMG which is always one of the hardest foods to deal with.)
Two slices. Which is much much harder than one slice.

Also we are using Fiasp in the X2 pump.

So we know this meal will have delayed carbs while the insulin will be fast with a short tail. Our approach is to use an extended bolus with a percentage up front and a percentage spread out over a period of time.

We forgot about the Basal-IQ.

So the regular bolus portion delivered and maybe 10 minutes into the extended. But then the Basal-IQ kicked in because there was an ever so slight drop in the BG of maybe 2 points. Basically something to ignore. But enough to kick in the Basal-IQ which not only suspended the basal but also cancelled the remaining extended bolus. And as mentioned, the extended will NOT resume when Basal-IQ releases but is simply cancelled.

We considered and decided this is simply outside the scope of what Basal-IQ is programmed for. And so turned off the Basal-IQ. Which only takes a couple taps on the screen - very easy. Then did the extended bolus again (but not the upfront as that had already completed.)

Now an hour and a half later we have turned the Basal-IQ back on (which again only requires a couple taps on the screen). The Basal-IQ would be able to suspend after 15 minutes as it requires a minimum of 3 cgm readings.

So it is very quick to turn on and off and is actively back online very rapidly.

A benefit of the Basal-IQ is the algorithm by all appearances is very simple so it is actually easy to understand what it is doing. If the situation is not appropriate, simply turn it off.

Next time (turning off Basal-IQ for a meal) the one additional thing I would do is set an alarm on my phone for 2 hours to remind myself to turn the Basal-IQ back on. Because I get distracted and forget. lol.

An interesting note. The Basal-IQ alarms are turned off. However when the extended bolus was cancelled by the Basal-IQ that did alarm. So actually that was ideal. Exactly as we would have hoped. That really was something we needed to know about. Which should always be the function of alarms. In my opinion.


Thanks Tim35 for the update! I am following your posts with great excitement as I will be due an upgrade in December and this is what I want to go with as a possible lead on a Medtronic pump fell through to DIY a closed looped pump.
And the best thing about a new Tandem is it will be new and covered under a warranty unlike an older used pump. And of course I can get the next upgrade (yes for a price but very willing) when it gets approved!
Keep the posts coming. I have pizza figured out currently so your tips will come in handy!


Good to hear that is it quick and easy to disable. I know I did the training, but to hear someone say that it only takes a few moments… That really helps!
And I do a number of extended boluses for larger carb and protein/fat meals. And I was concerned about it cancelling the extended bolus and I would forget to do it myself.

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Actually it is not yet determined if there will be an additional charge to the existing [in-warranty] X2 customer for the Control-IQ/HCL update which is forecast for launch in Summer of 2019.

There is a cost [rumored to be in the range of $200] associated with the Control-IQ algorithm which is due TypeZero (recently acquired by Dexcom) however who pays that cost has not been announced.

I think it would be better for everybody involved (including the company) if Tandem picks up the cost for existing customers and builds the cost of the TypeZero license into new pump purchases going forward.

There is a big Tandem conference next week so it is possible we could hear something regarding this. There are quite likely thousands and thousands of people wondering exactly the same thing.


Control IQ is in its pivitol trial now and will be released in 2019. That is a full hybrid closed loop artificial pancreas. That will be miles ahead of MT because it won’t need to be calibrated at all (vs 3-4x/day) and will be able to give boluses for high BG (not just increase basal).

Basal IQ already has many advantages over MT. Specifically, it uses Dexcom G6, so best in class accuracy, 10 day sensor life, and no calibrations.

It definitely seems to take IOB into account. It’s very eager to suspend for flat normal numbers if there is IOB. With the faint degree of gastroparesis I have this has caused me to need to wait until I see an upward trend on my Dexcom graph to bolus for food.


Anyone else using the X2/G6 basal IQ? Please provide feedback and reviews as I am about to lock in on this pump for 4 years…


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I’ve already commented here quite a bit, but I’m happy to answer any questions you have as I’ve found the system quite impressive. There is a tandem user Facebook group that has a lot of people’s experiences posted.