Thursday, October 4, 2012

t:slim review

UPDATE: I am no longer using the t:slim pump. It wasn't the right choice for me after all. I had issues as an Apidra user and had concerns about inconsistent basal delivery and worsening control. I understand I'm part of a small but significant group who had trouble, but Tandem is listening to the handful of us with problems and hopes to resolve them. Anyway, here was my initial review.

I started pumping this week with the new t:slim insulin pump from Tandem Diabetes Care. I have been watching and waiting for this pump to come to market for years and can hardly believe it's ticking away on my waistband as I type this.
This is not me typing this.
Many of you have been asking me how the t:slim compares to the pumps I've used in the past.

Here is the t:slim pictured with the three pumps I still have in my possession: the Omnipod first generation PDM, the Omnipod UST200 PDM, and the Deltec Cozmo 1800 (my 3 Medtronic pumps went the way of trade-ins). It's slimmer than any pump I've used before - about half again as thick as my iPhone 4S in its Speck case. Not THAT much slimmer than a Medtronic or Animas pump, but still thinner. (I compared it to my student's Paradigm and it was only barely so.)
I know - he's delicious.
My favorite part so far is that they moved the luer lock connection further down the tubing so that there is no stress on the tubing where it connects to the cartridge. I've had a baby or a toddler on my hip for the last couple years. When wearing a tubed pump, I frequently poke them with the luer lock cartridge port on my Cozmo. Not now. Clearance for those yummy chubby thighs.
Insets, IV prep, Verio IQ, cartridges/syringes/needles
t:slim box, charging cable, adaptors, cartridge remover keyrings,,
and the user guide is a business card thingy w/ USB input - wow.
The supplies take up more room in my meter case than I'd like. Your set change and cartridge implements are essentially in four separately wrapped pieces - 1) whatever infusion set you choose (I'm using the Animas inset, my favorite), 2) a flat black cartridge, 3) a fill syringe, and 4) a capped needle similar to the Omnipod fill needle. They package the latter 3 implements in one small black and white box, so that's nice. I just have to make sure I grab one of each item. Consolidation would have been nice.

I am always critical of pump clips and the t:slim delivers nicely on that point. A swivel belt clip with a soft felt lining to help the cased pump slide in and out. I'm looking forward to the t:clip, too - a case+clip in bright colors being developed by Myabetic.
Charging Cables and Assorted Tech Gear
Charging cables. I have a bone to pick with Tandem about charging cables. The t:slim's revolutionary lithium polymer battery requires a charge once every 7 days and does well if topped off for 10-15min every day. They send you a USB wall charger and a USB car charging adaptor (for a cigarette lighter) - and only one cable. One.

Luckily, I keep a spare micro-USB cable in my car for my husband's Samsung Galaxy series phone and it easily topped the battery off while I was driving today. But why send only one cable? Isn't the point of having the car adaptor in case I need to charge it on the go? Do they really want me lugging a cable around in my supply case or my purse? Have you seen what I do to headphones?
Thank you, Samsung. Apple, why you gotta be so proprietary?
Touchscreen. Oh my heavens, it's lovely. The glass and the colors (which denote different information types and whether or not it's a value that can be changed by the user) are crisp. It's not exactly like using an iPhone, but you can quickly adapt to the required pressure for button pressing. The touchscreen input means that you can pair it with any blood glucose meter you prefer to use. No scrolling up and down to input blood sugar values. Just a quick keypad input for BG and for carbs.
Touch me.
Carb calculator. This was the feature that surprised and stupefied me. There is a calculator for inputting your mealtime carbs. Sandwich was 28 and chips 17? No problem. Press "28 + 17 =" and hit Done. I'll never do addition again.
6th grade math teacher: You're not going to have a calculator
on you everywhere you go. Ah, how far we've come.
I LOVE that they have delivered on a failsafe for insulin overdose. There is essentially a holding chamber that they call a micro-delivery chamber in the cartridge that can hold less than a unit of insulin at a time. You're not ever at risk of a pin or plunger suddenly delivering the entire contents of your 300-unit reservoir into your body. Whew.

Loading the cartridge. There are three little idiosyncrasies about the way you fill the cartridge and tubing for the t:slim. 1) The cartridge is inserted before you fill it with insulin. 2) The fill syringe needle is very long, yet only the very tip of the syringe is inserted into the fill port. You feel a little pressure and stop. How many people will break a needle attempting to jam the whole thing into the fill port? Very odd. 3) When priming insulin into your infusion set tubing of choice, prepare for a wait. I'm a 23" tubing length user myself (short length) and in the time it took to fill the tubing completely, I could have gotten up and made myself a cup of coffee. Or gone to check the mail. It takes that long. Hmph. Update: I timed a prime and it came in just under 02:30. =\

So much makes SENSE about the way this pump works. If you time-out on a screen and go back into the pump, it remembers what screen you were on. It pulled the best features from the Cozmo pump (a site change reminder every three days, a missed meal bolus reminder) and the large reservoir capacity previously offered only by Cozmo and Medtronic.

The best feature, hands down, of the t:slim is the way it presents your settings to you.

With the other pumps currently on the market, the user is able to set multiple basal insulin profiles (for work, for weekends, for differently scheduled school days, etc), but you can't create multiple profiles for your correction factors, your insulin:carb ratios, or your target blood sugars. Those are stuck. When I was preparing to go into the hospital to give birth to Dibbs, I could quickly switch to a post-partum basal profile, but I had to go in by hand and change all of my settings in the other screens.

The other pumps split this data into multiple screens, embedded in different areas in the pump.



On the t:slim, it's all in one place. One place. ONE SCREEN EVEN. I can create (and even duplicate and then edit) profiles that are displayed based on time of day. I can look at a glance and see if my correction factor may be overcompensating for my basal rate being off. It's all in one location.
These settings were set by my Evil Genius CDE in regard to my
personal blood glucose trends. Please do not make adjustments
to your regimen without consulting your physician.
From the lock screen, I can see the time, date, battery life, insulin volume, and my insulin-on-board amount and time remaining.

Easy as 1, 2, 3.
And if I go into my History and click Delivery Summary, I can even get a visual breakdown of my usage for the day or over different specified periods (7 days, 14 days, etc).
Rock me, Amadeus.
This baby seems to have it all. I'm excited to see where this company is headed with their future iterations of the t:slim and I'm thrilled to have another competitor enter the market to push their rival companies to keep innovating for the end user.

I have consistently said two statements over the years when talking to people with diabetes about our available choices in regard to insulin pumps: "There is not a bad pump out there; they all get the job done." And "No one pump has everything I'm looking for."

I'm optimistic that I might be able to stop saying the latter.


  1. Oh what a wonderful review! It looks fabulous. Certainly an option for G as she grows into the teen years. Looks like it would engage a user, and not look so medical. I love that about it. Love the technology - could other pumps please jump on board???

  2. Believe it or not, that last screen is my favorite. I am slightly obsessed with keeping my basal/bolus at 60/40 or less and the Animas gives you the number but not the percentage (like MM does).

  3. Awesome review! Thanks! To Sara's comment about the % of basal/bolus - Omnipod offers this and that's great - but it doesn't break out the summary bolus by correction and food like the t-slim. Envy.

  4. Thanks for this review. I'm still dreaming as it isn't yet available in Europe but hopefully by the time it is, they will have figured out a deal with Dexcom! The one thing that would definitely drive me nuts though is the time required for priming the tubing. I prime my Cozmo reservoirs manually since it is so much faster. But i imagine that a manual prime isn't possible with the t:slim since the reservoir is already inside and there is no plunger.

    1. No, a manual prime wouldn't be possible here, unfortunately. I timed my most recent tubing prime and it took 2m30s. Felt like an eternity! Takes me back to the 2min blood glucose monitors from the early 90s.

  5. Do you have any issues with bubbles in the tubing and/or cartridge? We always are so careful with loading insulin in the cartridge and tapping like crazy to release all the air before inserting into the animas pump. Just wondering if this is even a problem with the tandem. Thanks for great review!

  6. excellent long detailed review, thanks! we had a chance to check it out at FFL and my kid loved it.

    lol @ 6th grade math teacher. :)

  7. I just started the t-slim on Friday. I have been a diabetic for 35 years and have used 2 different pumps Disetronic and Cozmo. This pump by far is easier to read and very easy to use. By far the best pump out there on the market today.

    1. Type 1 for 33 years. 6 years on Disetronic H-tron. $ years on Animas. This is a wonderful pump. Refill is slow. A lot of the commands take you step by step through everything(a little too much so. Makes things a little slow at times) Even with that I would rate my first impressions a thousand times higher than any other pump on the market. I'm tough on pumps. we will see how well it last in a couple of years. Customer service is excellent(as it seems to be with all brands) I would highly recommend it.

  8. Just found out about t:slim - been on Cozmo 4 years next month ( of the 'last' new users). One thing I'm going to miss greatly is the integrated BG tester. Why doesn't anybody make a pump like that anymore?? I hate carrying a bunch of 'stuff'

  9. Any concerns about the slow bolus delivery vs. the animas ping?

    1. I haven't used the Animas ping, but so far, I have no concerns about the bolus delivery speed on the tslim.

  10. I have been using the t:slim for about a week now. I have been pumping since the early 80s and the t:slim is my 5th pump. I am a bit baffled by the bolus calculator and feel that in certain situations it cannot be trusted. It fails adjust downward the reccomended amount of bolus for a given number of carbs when your BG is on the low side or more precisely no reduction in bolus is shown unless your BG is less than 70. This can cause over bolusing.

    We all know that if you decide to eat 25G of carb and your bg is 75 you will bolus less than if your BG is 130. The t:slim bolus calculator doesn't seem to understand this. If you enter a BG of 120 and 25G of carb the calculator will suggest a bolus based on your initial settings. If you enter a BG of 72 and 25G of carb the bolus calculator will suggest the exact same bolus which, in my case, leads to hypoglycemia. Although I am not sure what the limit is on the high side, but if you enter a BG of 150 and 25G of carbs you again get the same suggested bolus as with the BG of 72 and 130. The method they are using to calculate boluses is flawed and potentially dangerous. if your BG is on the low side of normal and you are getting ready to eat don't listen the the t:slim. It obviously didn't do well in math class.

    1. I've recently become aware of the t:slim and have been researching and am quite pleased to see the advances over the Medtronic and Animas pumps both of which I have experience. I'm also glad to see that some of my original pump's (Cozmo's) user-important features have been reintroduced to the t:slim. Of the two 'negatives' that I've uncovered thus far(both of which have been pointed out in the other user's entries), the one that Tandem should review closely is the one of which you speak. Having to exceed this fixed designation of 70 mg/dL BG before a 'negative' amount of insulin is applied to one's bolus amount is not acceptable. Basically, my opinion is that a "bolus caluclator" should present the recommended bolus value based on conditions as they exist at that moment in time. That is, the 'target BG' has been programmed into the pump. The calulation should not exclude application of a negative insulin amount because an arbtrary fixed value has been preset for the user. Bottom-line, this bolus calculation should be inclusive of: associated insulin for carbs as per the chosen insulin:carb ratio for that time of day, remaining strength of IOB based on the Insulin duration factor pre-selected by the user, and BG and the ISF (Insulin Correction Factor); i.e., insulin amount: xx mg/dL BG. Granted, the t:slim allows one the flexibility to alter the quantity of insulin 'suggested' by the 'calculator', but for me personally, I do not want to manually recalculate virtually every intended bolus considering it is a rare occurrence to exactly hit your target every time you check your BG, right? This currently would not be a step in the process of delivering a bolus viewed as user-friendly. Hopefully, Tandem will be open to reviewing a re-work of the 'bolus calculator' formula and its resultant presentation of a recommended bolus amount to the user.

  11. I was recently diagnosed with Latent Autoimmune Diabetes and have been considering a
    pump. I was focused on the animas because I often swim laps for two and a half hours.
    The t;slim sounds awesome and I am wondering if it can be used in the water. Can any user compare the animas ping with the t'slim for me?

    1. No you can absolutely not put it in water. Not water tight and will void warranty. They tell you up front that it cannot be in water. I myself am tired of tubes so I am thinking on the new upgraded omnipod.

    2. It is water tight for a certain amount of time and depth (i forgot the exact numbers) but people in the t:slim support group on facebook I am in talk about swimming with it all summer with NO problem what so ever! You can get it wet, just don't go on extended scuba diving adventures with it.

    3. Not trying to give medical advice, but I swim as well. When I swim I disconnect. Yes even for a 2 hour open water swim. Also for triathlons. I have found that I burn enough energy that I don't really need much insulin. When swimming in a pool I check my sugar every 30 minutes. I can hop out and shoot up real quick if I am high. The whole process only takes about 30 seconds

  12. Really wonderful review. Thank you for taking the time to write it. It's helpful to me.

    I've been on the syringe for about 3 years now and my endo said yesterday that it's time for me to consider transitioning to the pump. I started looking into them last year before the t:slim was launched and I'm really leaning to it as my first pump.

    I am both excited and apprehensive about transitioning to a pump but your review has helped me feel better.

    Thank you. :)

  13. Thank you for such a detailed review and description. I am considering switching from the Omnipod to the t:slim and your review is extremely helpful.

  14. Also, know that this pump does NOT like Apidra as well as Novolog. Mine gave me occlusion warnings several times, and I was told by support that there are several complaints about the tendency for Aprida to seem to 'crystalize' making it harder to push. I switched back to Novolog and have not had the problem since.

    1. I found that out fairly soon after trying this pump, fred.

  15. This is wonderful to hear. I am new to pumping and have never pumped and was just diagnosed with type I not type II in December of 2012. I have been trying to get a pump since then as I am a single Mom and both the expense and stress of being a type I isn't easy. I hope to receive the TSlim within two more weeks! Yay and reading your review is just wonderful news!! Thanks so much! ;) Sheri sherims1

  16. I'm curious now that you have been on the t-slim for a while whether you feel it gives you better control. I am on a Medtronic Paradigm and need to get a new pump. I am wavering between staying with Medtronic and switching to the t-slim.

    1. Sue, I've since left the t:slim because my control worsened. See detaiils here:

  17. Melissa, I'm sorry to hear that your control worsened. I'm on the T:Slim since December and my A1C is the lowest I have ever had. I used Apidra in the beginning and found out immediately that the T:slim doesn't do well with it. I switched to Novalog and have the best control now.

    Sorry that it didn't work for you, but wishing you good #s with the new Omnipod!