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Guest Post: Reviewing the tSlim.

I haven't had a chance to wear the tSlim myself, but I did receive an email from Chad Oswald from Louisiana, who made the jump from Medtronic to Tandem.  He's 43 years old, living with type 1 for 17 years, and is on the board for the NW Louisiana chapter of the JDRF.  He wanted to share his first impressions of the tSlim, bullet-point style. 

Chad, the floor is yours, and thanks for sharing today!

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Image from TandemDiabetes.comLet me just say, I’m not that young nor very "hip," so change is not something I readily embrace.  However, since I took my Medtronic insulin pump for a swim this summer, I’ve been forced to get a new pump.  Having pumped for over six years, I have my routines pretty much nailed down.  To be clear, Medtronic has always been great, they even over-nighted a loaner pump for 90 days when, due to my stupidity, it became waterlogged.  Still, I wanted to see if there was any new technology that would make managing this frustrating disease just a little easier.  

Taking a Chance
I decided to take a chance on the new t:Slim insulin pump by a new company, Tandem Diabetes.  I loved the look of the pump, and who wouldn’t? It is iPhone-like in terms of clean lines, slim form factor, and a touchscreen to boot! Honestly, I was tired of the old pump designs that exist currently; I didn’t want to waste my upgrade on the same old thing IF this new “sexy” one was any good.  I did my research the best I could and spoke with the company, but even so, I had many concerns: 
  • Tandem is a New Company - I was apprehensive about placing my health care and quite possibly my life in the hands of an unknown entity.
  • Durability – Was this just a cheap knockoff of the iPhone design craze? Could it hold up to the abuse of daily use for 5+ years?
  • Rechargeable Battery – Would it live up to the billing and how long would I have to wait to charge it, and would it deteriorate over time.
  • Cartridge & Reservoir  - Insulin delivery is different than Medtronic and I wondered how cumbersome the change out process would be
  • Quick Bolus – I primarily do manual “quick boluses” and didn’t want to lose the ability to bolus without having to look at the pump.
  • Menu/Data – Is the menu a maze of confusion and would I be able to find all the data I prefer to look at?
As I opened the package, I was excited and relieved at what I found.  The pump was even smaller than I imagined and more than anything it had a quality build and substance about it.  After 3 weeks of use, I’ve had the following impressions about my concerns:
  • I spoke extensively with the company and was encouraged by their friendliness and patience with my questions.  They handled the paperwork quickly and efficiently, and had the pump in my hand within two weeks.  In the end, it’s a leap of faith in a way, but if the company could design, build, get this kind of product FDA approved AND to market, then I’m willing to give them the benefit of the doubt.  
  • Durability WILL NOT be an issue.  This pump is substantial in build quality and in materials used.  It’s tightly constructed and the quality is evident.  However, it is not completely waterproof, it’s rated water-resistant or IPX7 standards, 3ft of water for 30 minutes.  So, I’ll still have to be aware of water!
  • The screen is AWESOME – Bright, sharp and the touch sensitivity is just right.  It also auto locks to prevent accidents.  It’s legible in daylight and comes with a screen protector from the factory.  I’ve read some complaints about not seeing the clock on all the time (oh please!) with the press of the “screen lock” button (the only button by the way) the clock and all important data appears in it’s colorful glory.  The home screen shows, battery life, insulin in units available, clock, date, as well as an alert symbol for anything that needs attention, and most importantly with a glance it shows the insulin on board (IOB), as well as how much time is remaining for it.  I cannot stress how much I LOVE not having to scroll for numbers!
  • The high tech lithium polymer rechargeable battery has been terrific, as advertised.  In fact, I love it.  I haven’t really let it drain all the way down, and probably have spent about 10-15 minutes a week to charge it back up.  It charges fast and I’ve been shocked at how long it’s lasted.  I’m hopeful it stays this good over the life of it.  
  • Changing the cartridge is different than I’m used to.  You fill the reservoir with a supplied syringe, and have to be careful NOT to jab the needle too far in the first time.  However, after doing it twice, it’s very easy and with the onscreen “checklist” makes sure nothing is done out of order.  Overall the process is a bit slower than my Medtronic, but not irritatingly slow, yet.  The reservoir holds 300 units, which is nice.  I’ve read some concern about air bubbles and not being able to see the actual insulin in the reservoir.  I’ll just say, I have not seen a single bubble after the initial tube filling. It’s possible I’ve missed one, but I saw more with my Medtronic.  It would not surprise me to see the reservoirs come pre-filled with insulin at some point.
  • Quick Bolus is AWESOME.  It can be done without having to look at the pump.  Press and hold down the ONE button on top of the pump, after beep, press again for each unit (or preselected increment), then pause, wait for confirmation beeps and then press and hold again, presto, bolus is given.  Each sound is unique for added help. 
  • All menus just make sense and are easily escaped by tapping the “T” on the right of the screen, which takes you back to home screen.  The bolus screen allows you to bolus by grams, which when entered turns the screen into a numerical pad with a +/= sign so you can simply enter the carbs for each food and let the pump do the math! 
  • The basal rate menu is terrific, very easy to see what your doing. You can create up to 6 unique “profiles” for each basal rate routine you may want.   Also, the profiles can each be customized for a different carb ratio or correction factor.  
  • Great collection of data and history, all with graphs that show usage patterns and averages over multiple time frames.  Again, the vivid screen makes these more pleasant to look at.
  • Safety – You can read on the Tandem website about the micro-delivery system they use that provides a level of added safety to the actual delivery of insulin. The system can deliver as small as .001 unit increments.  Also, to protect against an over-bolus the numbers will “grey” out after the first number is selected.  So, lets say you are going to bolus 3.5 units, after you press the “3”, all the other numbers will then grey out with only the decimal point being active to press.  This way you don’t accidentally skip the decimal and bolus 35 units (of course it sets a limit on the maximum bolus amount in the settings menu anyway).  I thought having to tap the 1-2-3 onscreen buttons to “unlock” would get old.  But it’s so fast and well done, it’s a non-issue and I’ve been thankful it exists on more than one occasion.
One Complaint
My lone complaint is the belt clip is a bit bulky, but luckily the pump is so thin I just keep it in my pocket.

Not every pump will be perfect for everyone’s needs and lifestyles. However, I would not let the fact that this is a new company or new product scare you from trying it.  This design will force the competition to get off their duffs and start innovating with more attractive and user-friendly devices.  Just like the iPhone has done for cell phones ... after all, how many of you are still using an old flip phone?

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Thank you, Chad, for your insights.  I'm looking forward to reading more from people using this new insulin pump.


I was looking at the t:slim also. Th only reason I don't have one is they were very slow in getting my insurance coverage processed (over a month) and in that time, I had to change insurance, so I went with the Animas Ping in the end so I could get it covered before the change. I am seriously looking forward to upgrade time so I can try the Tandem pump. Funny thing, I had the same concerns about a "new" company and I haven't pumped before! (Just started 2 days ago!)

Thanks Chad!

I appreciate the hands on. Any issue with un intended touch screen butt dialing?

Thanks for posting this! I have been looking for a review of this new pump. I'm a long-time MM user and am intrigued by the t:slim. I'm cautious to make the jump, mainly because the company is so new at this point. It makes me hesitant that they will be able to back this product over the long-run. Buying a pump is a total commitment (moreso than a cell phone!) so you really need to know the company stands behind the product. I'm not quite ready to make the switch yet due to the cost, but if the reviews keep coming in good, I might consider.

@Marcie - I'm sure they are still building out the distribution networks, I know there has been a shift in insurance agreements with many "durable medical manufactures" including medtronic, so they use distributors like Edgepark medical for the actual insurance agreements. That may cause some delay.

@Bennet - LOL.. No the screen auto locks or you can "lock" it by pressing the activate button. Once locked you have to hit a "1-2-3" onscreen button sequence in quick order to access functions.

@BustedPancreas - yw, I totally understand and I was nervous about it as well. However, ultimately I felt like they did a heck of a job on a great new product and wanted to support that effort. I also felt that management had proven history in biotech & diabetes related management. Your right, time will tell.

I was just having this discussion with my husband last night. I am a long time MM user and I am just fustrated. I am out of warranty as of 10/5/12. I was at the endo on the 5th trying to decide between the tslim and MM again...still haven't decided. The main things I have been worried about you have discussed. Just curious how bulky are we talking about on the clip with the pump in it. I have had a chance to play with it a little in the endo's office but was curious about real life application.

Thanks for the review, Chad!

So what has your experience been like with their infusion sets?

I am curious about this pump. I have a Medtronic pump and CGM, does the t:slim support any type of sensor? I have gotten used to being able to see my sugar levels all the time.

We got the tslim for my 11 year old daughter. She had been using the animas pump for about 8 years and we were ready for something new. We LOVE the tslim! Stephen, you can use the same infusion sets you have been using, so my daughter continues to use the inset 30 she had been using. My biggest worry was about having a rechargeable battery but we have about a 30 minute drive to school in the morning and she charges up by plugging in to the cigarette lighter. It works great and charges quickly, so no worries there. She wears a dexcom also, so that is where our cgm info comes from. It was so easy to switch over to, seeming natural to use immediately.

Ha! Just saw the ad for this pump yesterday and was curious about it. Thanks for the timely review. Sounds great! Sadly our pump is only 5 months old...so it will be a while before we can make the upgrade.

Thanks for the review, Chad! Very helpful. We are looking into the TSlim as well and wonder your thoughts on the 'floating lure'? Seems like it would snag on things and be a general nuisance. Any thoughts?


@flmgodog - The pump comes with a great "slider" case that protects the body, and also comes with the belt clip, which has a good design, it slides over the pump body and swivels, but adds bulk... it's the swivel that causes it to "stick out". Also, the actual clip part is just a bit big. They have other options, you may want to ask about.

@ Scott - yw... Thanks to you for all you've written/shared over the years!

@ Rebecca - No CGM as of now. I'm with you, I use Dexcom7 and am excited about the G4. They are working on integration with Dexcom (aren't they all), but I have no idea on timetable. Considering how fast they got this pump to market I'm hopeful it will be relatively soon and can be done with current pump. It's funny though, I keep this pump in my pocket and my CGM is usually out on table,desk or cupholder in my car, I don't mind not having to dig my pump out of my pocket every time I want to see my CGM. But no doubt two devices is more of a chore.

@Stephen - I'm used to the Silhouette sets from Medtronic. Tandem sent me basically the exact same thing, by Animas actually. They only thing new to me is the "luer lock" connection, but it's a total non issue and they extended the cartridge tubing a couple of inches from the pump so the connection doesn't pinch. I wasn't sure how I'd like that, but it's great.
The whole change out process is a little bit more time consuming but not terribly so after doing it a few times. I like using the syringe to first draw the insulin as it allows me to get rid of the bubbles better than what I could do with the mm setup. Hope that helps!

My MM pump is out of warranty and I am planning to switch to Animas or Tandem because of the future Dexcom integration. The Tandem looks really interesting with some very unique features and a definite "wow" factor.

Unfortunately Tandem has not yet put an upgrade program in place. Until they can guarantee an upgrade for a reasonable out-of-pocket price to their next generation Dex integrated pump, I'll have to pass.

Of course for both Animas and Tandem, there's no guarantee when the Dex combo pumps will be released anyway. Years go by with these things just around the corner....

My daughter just went "live" with her new T:Slim pump yesterday. She has been a Cozomo and Animas Ping pump user prior to this. Was happy to hear that Tandem bought many patents from the makers of the Cozomo pump. Love the ease of use and she found the pump very intuitive to use. She loves not having to press up and down arrows to enter information. It will be nice down the road when the meter will talk to the pump. But love the new technology and will to give that feature up. The clips on the case are too big, but just took off that part of the case. She uses Cleo infusion sets she has been using since starting pumping.

Naive question: does the pump keep pumpin' while it's charging?

I just this morning, received the great news that my appeal for this t:slim insulin pump was APPROVED!

I'm very happy, and also looking at my PDF's I've downloaded to study for the How-to's in working this new device.

Happy to ready the review. I'm 56 and partially-sighted, so this is looking even better than before.

Yes, it continues pumping while it is charging. It has a stop insulin feature like other pumps that you would choose if you didn't want it to. (Because you we're downloading and charging it to your computer, for example)

I've been using the t:slim for a few months now, and am equally as satisfied. For those among us who don't care for the t:slim belt clip, I've discovered the Minimed belt clip actually fits pretty well around the t:slim. It doesn't lock on so I don't recommend it for activities that require a lot of durabulity, but I use it when hanging out around the house or wearing pants without pockets. Just a tip!

We want to get the tSlim for our son, but his doctor is saying he won't write a rx for it because it's not FDA approved for children under 12. It sounds like there are a bunch of kids using it and loving it. If anyone has info on kids using the tSlim, if you could post about it I'd appreciate it!!

Hi Chad,

Thanks so much for your review. I was wondering if you could tell me how large the insertion site is (ie how far does the site stick out from the body? Is it larger or smaller than a quarter?). I am thinking about going back to the pump after many years off and am looking for a pump that's pretty discrete. Do you think this is the smallest pump available (in terms of size of site, size of the pump is not as much as a concern for me) or are there others that are smaller?

Thanks so much!

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