MiniLinked! My Turn with the Guardian RT

So I’m hooked up… I finally got my chance to try Medtronic’s MiniMed Guardian RT, the only other continuous glucose monitoring system currently on the market besides the DexCom. I am one of the few who’s had the chance to sample both. So far, it’s been a somewhat bumpy beginning, which leads me to believe that my initial conclusion was spot-on: CGM is a great idea that’s still in its infancy and not quite ready for prime-time.

Allow me to break out a few details on my “first look” at the MiniLink sensor…


First off, this packaging kind of threw me for a loop. Does this imply that the MiniLink will allow me to once again indulge in my favorite food in the whole wide world — carrot cake with cream cheese icing? Sadly, I think not.


Second, the Guardian receiver looks exactly like a MiniMed insulin pump. Because it IS a MiniMed insulin pump; it’s made from the same casing, that is. Economies of scale and all that. But since I’ve never used a traditional insulin pump before, it feels weird to have this pager-ish thing hanging off my belt all the time. I can’t tell you how glad I am that I’m not attached to it via long plastic tubing.


Third, this marketing photography is a little deceiving. Like those who’ve tried the MiniLink before me, I’ve discovered that the “shell” portion flops around freely unless you cover the whole thing completely with a clear medical adhesive patch from Smith & Nephew (provided with your Guardian RT supplies).



Calibration is a heck of a lot easier with the Guardian that with the DexCom, for sure. All you have to do with the Guardian is push some buttons to plug in the BG result you got with your regular fingerstick meter — whichever model that happens to be. No need to hook the CGM up to any traditional meter via cable and hope that the two can communicate.

Alarm tones are much softer and less intrusive than with the DexCom. Good for sleeping. Good for our marriage :)

Record-keeping prowess! The Guardian has that MiniMed feature set that allows you to “capture event” — meaning you can input every BG result, carb count, insulin dose, and exercise session if you want to. Then use their CareLink software for complete records download. I haven’t tried that yet, but it sounds powerful.


So far, on Night 1 the unit missed a 220 reading — it had me at 144 for hours. Dern!

I also lost the first sensor because the rep insisted I try it on my lower back (see pix), and the cannula popped out on Day 2.


I’ve had “lost sensor” reading 3 times already, for no apparent reason.

And right at this moment, the Transmitter is telling me that the battery is dead — after just 4 days of wear.

Hmmph. I charge on.


19 Responses

  1. Ali
    Ali February 20, 2008 at 8:26 am | | Reply

    The best description I’ve heard about getting used to CGM was from Nick commenting on “Having a CGM is like having your first baby: there’s never really a “good time” to start, you really never can afford it, it takes an incredible amount of work and patience, and you have to catch it when it first messes up to keep it on track. But once you’ve had it a while it really grows on you and you wonder how you ever got along without it to begin with.”

    Thats so true. I’ve been using the Minilink for 12 months now and would hate to be without it. I think it probably took me about 3 months to get to the point where I was 100% comfortable with it.

    I find its accurate most of the time, the only time it isn’t is when I’m falling or rising really fast. But, and this is the important bit for me, the trends are always spot on. So, if it says I’m rocketing up and am currently 200, I’ll generally do a blood test to check as I know I’ll probably be higher than that. Before the CGM I wouldn’t have even known I was rising so could have been high for a good few hours before I knew.

    My HbA1c results have really benefitted – down from around 7% to 5.5%

    Warning – one downside is that it’s very disappointing when you discover that wearing the Minilink does not make your stomach as flat and toned as the model in the picture!

  2. MoHo
    MoHo February 20, 2008 at 8:43 am | | Reply

    Yep, I had a similar experience. The biggest problem I had was that the MM did not catch more rapid changes which the DC did. I am kind of surprised that a big, well respected company would put out such a buggy product.

  3. christmasx2
    christmasx2 February 20, 2008 at 9:30 am | | Reply

    I tried the Dexcom 2 weeks ago and loved, despite its bugs. I am waiting to get a trial with the minimed product, hopefully within two week. CGM is fantastic. I must get, even though I will hate paying for it. BTW, the new Dexcom, due out 3/3/08 will allow manual input for calibration.

  4. Rachel
    Rachel February 20, 2008 at 10:20 am | | Reply

    I’m interested to see how it goes for you. At the moment, I have no desire to be on a pump and a CGM.

  5. Cara
    Cara February 20, 2008 at 10:44 am | | Reply

    I am starting week 2 with the Mini Link. I agree w/ Ali that it’s a major disappointment that my stomach does not look like the model in the picture. Sigh.

  6. Kendra
    Kendra February 20, 2008 at 1:51 pm | | Reply

    MoHo, just wanted to chime in that the Dexcom had the same issues with rapid changes that you describe the MM having when I wore it for a trial. Precisely why I decided to pass on CGMS technology until EVERYONE works out the kinks…I agree with Amy, I just don’t think this is ready for prime time yet. But when it works, it’s pretty darn awesome.

  7. MoHo
    MoHo February 20, 2008 at 3:39 pm | | Reply

    I wore them both at the same time for a while. For me the DC has worked a lot more reliably than the MM keeping track of rapid changes, the MM just wouldn’t show any change until about 30 min (or more) after the DC would show a drop or rise. I have been using the DC continuosly for about a year now and it has worked pretty well, I sent the MM back.

  8. jacque
    jacque February 20, 2008 at 4:26 pm | | Reply

    I received my Guardian in October 2007 and have also had some ups and downs with the unit. During my first 10M run with the MM, the transmitter and sensor fell out. Since then I’ve found that “painting” my skin with 3M Crack Care before removing the white tape, letting it dry for about 10 seconds and then removing the white tape and pressing the the sensor down works wonders. I then take the IV3000 tape, cut it in half and place the 2 halves in a “X” over the transmitter and sensor. I do high intensity workouts 5 times per week and have never had a sensor fall out or come loose. I normally wear the unit 6 days, showers and all. I’ve tried 7 days, but the readings never really tracked my BGs on the 7th day.
    Be thankful you don’t have one of those flat stomachs. I have very little body fat and inserting the sensor is often painful and getting to the interstitial fluids in a lean body seems to affect the SG readings.
    In addition to running I also do several cycling classes a week and have a feeling that all the digital “noise” from 40+ wireless heart rate monitors can influence your SGs. Often I’m flat lining for the whole class, even though I take 40-65 gms of carbs (PowerAde) over the hour. I understand that Dex is also looking into the “noise” issue.
    Of course we early adaptors are on the bleeding edge (that too) of technology and I’m sure with our feedback we will help improve the CGM units each year.
    If possible, it would be great if a thread could be established for CGM users. It’s been tough to find other users and share concerns and tips.

  9. Lauren
    Lauren February 20, 2008 at 10:41 pm | | Reply

    I’m all for diabetes technology but sometimes it seems like managing all these devices is a full-time job in itself. I am a low-tech injector right now, and fine with that for the time being, although I am curious about what else is out there. (The two other type 1 diabetics in my family are so old school they are suspicious of those “new-fangled” insulin pens, let alone pumps, pods, CGMS and all the rest.) Good luck to all of you pioneers who are working out the glitches for the rest of us!

  10. Mark
    Mark February 20, 2008 at 11:00 pm | | Reply

    In an article I just read in EE Times – the following is written: “Medtronic engineer presented an update on efforts to build an artificial pancreas. Medtronic already provides an implanted insulin pump that’s activated manually, but the new device would automatically check blood-sugar levels and provide insulin as needed. We’re working on a new algorithm, and we are confident this is the one we will put our chips on.” All we can do is wish them the best.

  11. Ali
    Ali February 21, 2008 at 1:37 am | | Reply

    Jacque has a good number of people using CGMS – you can always find lots of tips and advice there.

    Hope that helps


  12. Jan
    Jan February 21, 2008 at 12:22 pm | | Reply

    Amy, please post more about your experience using both the Dexcom and the Guardian. I am very interested in your experiences with both and which one is more accurate, in your opinion. Comparison information would be very helpful as most people cannot afford to buy both. My niece has the Minimed pump and we just started using the sensors. Main objection we have is the large introducer needle. We use EMLA to numb and she does not feel insertion, but her arm does get sore sometimes later on. We consistently get 9 days (but cannot seem to get more) out of each sensor if work on her arm. Sensor does not track high BG and low BG exactly. It tracks the trends. In our case, if sensor reads 180, she is 20 to 30 points higher than that. If it reads 90, she can be 60. However, she has never gone lower than 60 on the sensor and usually 70. We are very happy with the sensor but I feel the Dexcom would be so much more comfortable to wear and insert. That is my main gripe. Is it?

  13. Angela
    Angela February 21, 2008 at 5:05 pm | | Reply

    I’ve been wearing the MiniLink for about a year, and I love the quote Ali started out with. Perfect!

    Amy, have you tried inserting the sensor horizontally? I could never make it stay in when inserted vertically. To control the flopping, I use BandAid Tough Strips. If you place one across the device from the tip of the sensor to the end of the transmitter, or slightly on the diagonal, it not only keeps the transmitter stable, but also helps keep the sensor canula in your body. Best of luck through the rest of your trial!

  14. Dan Fahey
    Dan Fahey February 22, 2008 at 8:58 am | | Reply

    I’m considering the Omnipod, which of course doesn’t yet have a CGM, and am interested in a separate CGM like Dexcom or Guardian.
    What Amy indicated seems to argue for the Dexcom at the moment and a new version would probably improve upon it.
    Amy, like another commenter, I’d love to hear more about your experience with the Dexcom. Also, what’s it like managing two separate systems?

  15. camille johnson
    camille johnson February 22, 2008 at 9:21 am | | Reply

    I already posted a bit about my experience with DexCom7 CGM (paid for out of pocket! How do you folks get in on trials?) but it wasn’t posted because (???) it was probably too negative. Let’s just say that I had problems with every single part (and there are many) of the kit. Although DexCom replaced most of the parts at their expense, there ware days of waiting for the parts to be delivered since they used the cheapest form of USPO mail. I am really disappointed that DexCom would put this product on the market when it is SOOOOO buggy.

    The final straw was when the blood sticks kept breaking because something in the monitor was jamming. DexCom refused to reimburse me for the sticks because “we don’t manufacture the test strips, and we are not responsible for reimbursing you if they don’t work.” I tried to explain that it wasn’t the strips, it was the monitor! They refused to reimburse me for the DexCom7 because it only has a 30 day warranty!!! 30 days??? Guess they know it doesn’t really work. I realized then that these people are desparate, to the point of being dishonest/ panic stricken / frantic …. Too bad. It’s a good idea but they’re going to get their butts sued. Any suggestions for getting my money back?

  16. Dan Fahey
    Dan Fahey February 22, 2008 at 9:06 pm | | Reply

    To Connie:
    Is this the brand new Dexcom 7?

    To Amy:
    Don’t you use the dexcom7? What’s your experience been?

  17. Brett
    Brett February 23, 2008 at 12:48 pm | | Reply

    My 7 year old son has been using Dexcom since the Dexcom 3 first came out. We have had good success with it and very, very good customer service from Dexcom. We put the “bug” (as we call it) on the back of his arm (the triceps area). Usually get about 8 – 10 days of use out of it. It gets more accurate the longer it is on.

    The Dexcom 3 was not waterproof which was a drag, but the Dexcom 7 is waterproof (the “bug” part — the receiver is not, so we keep it in a ziplock if swimming).

    The syncing with the Ultra is an irritation (our usual meter is Freestyle Flash, so it’s annoying to have two meters) — it’s nice to see that they’re getting rid of that restriction.

    To Camille, our warranty was much longer than 30 days, and Dexcom even replaced the receiver once when we lost it at a baseball game. Not sure if something changed since we bought ours or not, but our service experience with them was much better (or luckier?) than yours.

    Oh, also to Camille or anyone syncing the Ultra to the Dexcom — it must be within range when you sync it or the sync will be wasted. I really wish the user interface was better in that area, and hopefully the next version will take care of it.

    One last thing: a CGM has been extra helpful in the winter — the freestyle flash is extremely inaccurate in the cold — but the CGM has retained good accuracy even in the cold…

    It has not been 100% accurate, though – as others have said, it will vary 10 – 25 points — but the trends are almost always right on.

    Finally, for the future (a year or two down the road), Dexcom announced partnerships (?? or whatever it’s called) with Animas and Omnipod to integrate their CGM with their pumps. Since we use Animas already, we can’t have it happen soon enough!

  18. Andy
    Andy February 26, 2008 at 10:12 am | | Reply

    Hi !
    Problem with MiniMed is that you need to buy sending device every 8 months (or so) and this is not cheap (around 1000 EUR in Europe). Problem is that sending device (white part on picture (Minilink transmitter)) has no exchangable battery, and after battery dies you need to buy new trasmitter. If your insurance doesn’t cover it, it’s quite a lot of money. Insurance company here where I live, covers Insulin pump (which supports this Guardian Sensor), but you need to buy transmiters and sensors by yourself (if you want to have it).

  19. meredith
    meredith November 12, 2008 at 4:04 pm | | Reply

    I have the new DexCom 7 and, although it does take getting used to, I am happy to have it. I have already picked up trends that I didn’t realize before my most recent A1C was 5.5 and that was only after about 6 weeks.
    My problem is that i am getting reactions to the filament of the sensor. Is anyone else experiencing this? It is super itchy and ends up leaving a lump under the skin when I take it out. The other thing that I don’t like is the (seriously) loud alarm that goes off during my classes. All of my classmates look over to see who didn’t turn their cell phone off.
    The customer service with DexCom has been pretty good. I lost the receiver recently and they replaced it free of charge.

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