Critical review of Tandem X2 Slim and Dexcom G5


Consensus is over-rated. :wink:


I doubt that the X2 bluetooth signal strength reception can be improved with a firmware update. They would not put out a product with a dangerous flaw if the fix was so easy. I think it is a hardware design defect. Works fine with the Dexcom receiver or a phone. It is a Tandem X2 design flaw. If you want a pump to be the only device needed to receive CGM data reliably, Tandem X2 won’t do it. I only use the pump with the face pointing outward and still have horrible results. Frequent out of range errors.
A pump with CGM compatibility (with no other receiver) seems to be unavailable at this time. It appears that Tandem dodges the problem and can’t supply a reliable fix. Reliable operation requires you to use a phone or Dexcom receiver in addition to the Tandem pump. That really sucks but Tandem has not offered me a solution in spite of their false marketing claims. I AM ANGRY. Lies and false marketing claims can kill people. Tandem should come clean with their design flaw and inform their users that the pump alone is not a reliable way to receive CGM data. If I sleep through an alarm and die at least my kids will get rich from the resulting lawsuit.


Believe it or not. Each person can evaluate their own version of reality.

The Dexcom to Tandem Bluetooth Low Energy (BLE) communication is improved with the Dexcom G6 Transmitter and the Tandem t:slim X2 pump running the Basal-IQ update.

This is a fact.

If somebody wants to continue to trash a product which apparently they do not use - well - it is what it is. Free speech and all.

It is great there are alternative products available. Many people are quite satisfied with the Medtronic options.


@Andy_S. I use the X2 with the G5, and rarely have a drop out except when I am seated in a deep armchair with a computer on my lap, or. I roll over on the pump at night.

I hope your experience gets better, and BTW, the Dexcom Android app is compatible with your phone if that helps.


And that would mean that the two algorithms that my wife and are looking forward to using, WON’T WORK reliably. sigh. first the stock market; now this. Life sucks. :open_mouth:


I repeat, I am getting RELIABLE SERVICE from my X2 and G6 combination.
Granted, I have only been on it a couple weeks now. But it works!

Now, I adjusted how I wear my pump, and I don’t have problems.

And like I said earlier, I had the G6 and X2 communicate through the floor for many hours. And this is an old house with real wood floors, etc.
The G5 would never have done this!

I would still prefer to have a BETTER signal strength.
But it WORKS. And the system works WELL.


Are you sure? The Android Pixel 2 XL is listed as not available.


I just received the G5 three months ago. G6 is not available to me under Medicare.

The G5 with the T slim sucks. Medicare won’t give me a replacement. I consider it my responsibility to trash a $6000.00 product if it does not work as promised.


Andy, my wife and I both wanted to get the x2 in December after seeing both it and the 670. We are both long time Medtronic pumpers but don’t like the 670 or the sensors. The Tandem rep and her manager told us not to get their pump (if we can hold off) until after medicare approves the Control IQ upgrade, because prior to that, if we buy the pump, it’s possible we won’t be allowed to get the upgrade code (or however tandem works it) to the Control IQ. Not to mention the G5 doesn’t work even with Basal IQ, so there’s no immediate reason for us to switch pumps. It seems nutty that we can’t simply get the X2 now and come summer, get the new features (presuming Medicare also switches us to G6 at that time) of Control and Basal IQ.


An admittedly imperfect solution is to pair both pump and receiver simultaneously and set the X2 alarms to vibrate overnight. The advantage is that it avoids the initial calibration and therefore the 2 hour wait.


Ditto. I’ve had the X2 G5 replaced several times due to this unforgivable nonsense. When I call Tandem Support they typically insist that it’s the sensor (if data loss) or transmitter (if signal loss). Most of the Support reps are specifically trained and do not have the background to see beyond that training (but there are a few who can understand my simplified technical explanations of why the pump is the culprit).

Another infuriating “solution” to signal loss is that they have changed the 16" separation limit to 2-3" maximum (as many of us know from experience). The point is that they apparently are not attempting to address this. What’s worse us that the Bluetooth sensitivity to WiFi interference could have been ameliorated by using a Bluetooth chip buffer.

One observation is that (for me at least) these problems started this year, along with significant inaccuracies. The main change that might be causative is the new Tandem facility on the West Coast that begain operations in January 2018. I’ve advised an open-minded and knowledgeable tech support supervisor to investigate this.


I neither stated nor suggested that I “know this” (as clearly indicated by “might be” and “investigate”), so this is your misunderstanding.

Rather, my knowledge of biomedical tech, quality control, and automation - coupled with the signal issue being discussed, the fact that I had not encountered this distance problem until 2018, and the new Tandem facility becoming operative in January 2018 - informed my inductive reasoning that an issue in said facility could be a likely possibility. (FYI, a Tandem tech support supervisor agreed with me earlier today.)

I trust this is clear.


Quote from your initial email: “I’m curious how you would know that.”

If you don’t realize that while your sentence structure is quasi-interrogative but the phrase “how you would know that” is a declarative assertion that I “know” something, then there’s nothing else I can do to help you understand other to note that for the sentence meaning to match what you think you said, you should have written “how did you arrive at that conclusion,” since an inductive (rather than deductive) conclusion is probabilistic.


One more issue with the P.O.S. Tandem Pump! I haven’t changed over yet from using the Dexcom G5 Receiver to just using the T2 but this does NOT surprise me. Their micro-delivery system is a BIG problem - they have problems with their cartridge, their Occlusion Alarm, and their “remaining insulin” calculator. How can you have what is a “precise” $6,000+ medical device that is 70 units off on a 300 unit cartridge? This is a life saving/threatening device. With all the problems that I’ve had with the T2 I do NOT know if I want it calculating my Bolus and Basel… What if it makes a mistake in the calculation like their micro-delivery system does or now their BlueTooth. And I’m not a “newbie”. I’ve been on a pump since 2001. In 17+ years I had less than 5 occlusion alarms on my Animas. In 5 months I had 8 occlusion alarms with my T2 and their answer was to “re-boot”. If you actually had an occlusion “re-booting” wouldn’t fix it. Finally got them to send me another pump and I have not had an occlusion alarm in 6 months after they originally claimed it was me. And they haven’t even callled to follow-up on the device. I really do NOT have much confidence in Tandem BUT I will be stuck with this for 4-5 years due to Medicare … unless I pay out of pocket for a Medtronic (if they ever get approved) or the upcoming Beta Bionics.


Is this a result of the move to BlueTooth communications? Is that a shorter transmission range? Somebody could address that concern on the FDA Bluetooth diabetes user feedback study that is posted, if it is.


You said “An admittedly imperfect solution is to pair both pump and receiver simultaneously and set the X2 alarms to vibrate overnight. The advantage is that it avoids the initial calibration and therefore the 2 hour wait.”

I tried that several months ago and it wouldn’t allow that. I was told you can pair with both a phone and the pump but NOT with the Dexcom receiver and the pump simultaneously. Unfortunately I have a Pixel2 XL phone which is not compatible with the G5.


I hadn’t heard that. Is that a Tandem specification with the X2 slim and the Dexcom G5? Two to three inches maximum? That’s ridiculous and impossible at night.

I assumed that the 20 foot range specified by Dexcom G5 was supposed to be true regardless of receiver?

I haven’t tried my new replacement pump as the receiver for my G5. I did that with my previous X2 and it was only reliable if I kept the pump in my shirt pocket. At night it would fall out of my pocket and go out of range. Then I strapped it to my belly with a Medtronic belt but it was uncomfortable and still often went out of range if I rolled onto my belly.


that should be feet, I think.


Oh yeah, probably. But I was only getting up to 16 inches max between my G5 and Tandem t:slim.

Oops, I’ve been saying Tandem X2 but I have the t:slim. Not sure what the difference is.


Can you give instructions or a link to where I can find it?