- advertisement -

My experience: Dexcom vs Guardian RT

Discussion in 'Continuous Glucose Sensing' started by someone, May 31, 2009.

  1. someone

    someone Approved members

    Joined:
    Feb 9, 2007
    Messages:
    126
    My experience: Dexcom Seven Plus vs Guardian RT

    Thought I would share a short comparison of these 2 devices. I have only been using the Dexcom for a week, so have a lot less experience with it.

    Sensor Insertion
    The Minimed's insertion is simpler and and more straight forward, but I like the Dexcom insertion better. First of all, the way the Dexcom's inserter is designed, it is much more difficult to mess up with the angle and the inserter needle is more likely to enter the skin fully. With the Guardian, if I was at all hesitant when pressing the trigger, it wasn't uncommon for the insertion needle to only make it half way in. Overall, the Dexcom may be a little less painful, but they are quite similar in that respect. It is much more difficult to remove the insertion device and connect the transmitter on the Dexcom, so this may make it less favorable for those wanting to place the sensor in harder to reach areas.

    Transmitter/Sensor design
    As far as the design of the transmitter and sensor go, both systems have advantages and disadvantages. The Dexcom adhesive patch is much better than the Guardian. So far, it has been totally unnecessary to use any type of dressing that was necessary to make the Guardian transmitter/sensor stay on. The Dexcom's patch is larger overall, but worth the size in my opionion given that it is much more secure. Plus, once you put Tegaderm or IV3000 over the Guardian's sensor, it's going to cover a larger area. As far as I can tell, the Dexcom's transmitter doesn't have a battery. My assumption here is that there is a small battery attached to the sensor...? To me this is an advantage because it takes off an extra 30 minutes of waiting every time the sensor is changed. Major drawback on the Dexcom is the the transmitter has no memory. This is something I didn't think of before getting the device. If the receiver is not in range, quite simply, you are losing precious data. On the other hand, the Guardian's transmitter stores 45 minutes of data, so you don't lose anything as long as you get back in range of the receiver within 45 minutes. As far as range, the signal strength is about the same on both devices.

    Receiver design
    The Guardian is a clear winner for me as far as the receiver goes, however, both leave much to be desired. The larger screen on the Dexcom may be attractive to some. Unfortunately, to me, it seems that it's there for no reason. That is, they aren't making good use of it. The graph on the dexcom is set to a 40-400 scale, so even if all of your readings are between 80 and 120, you're stuck looking at a graph with a vertical scale of 40-400. A waste of screen space? Tell me about it. So if your eyes are bad, don't let the larger screen lure you in. Additionally, on the Dexcom, there is no way to view specific data points on the graph. The Guardian has a cursor that allows you to scroll through the data points on the graph. Lastly, the Dexcom receiver also needs a 3 hour charge every 3 days. Now why in the world they would do this is beyond me. They picked the wrong area to go green. I tried letting it charge overnight, but the transmitter signal didn't make it to my night stand which cost me a whole night of data.

    Accuracy
    To be honest, I don't have much to say here. From what I can tell, accuracy of the two devices is very similar. With the Dexcom, I sometimes get one data point that's way off of the others (ie noise), but that's rare enough for me to ignore. For both devices, accuracy is highly dependent on where and how the sensor is placed.

    Calibration
    Dexcom is the winner here. It doesn't just stop giving you data if you don't calibrate within a 12 hour period. Just a notification that it needs to be calibrated. The Guardian forces you to calibrate at 12 hours which is a nuisance especially if it happens to be at a time that isn't ideal for calibration.

    Software
    Carelink (Minimed's web based software) is easier to use and can be accessed from any computer. Dexcom's DM3 provides slightly more analysis capability, including graphs annotated with food, insulin and exercise data, but for me this doesn't make up for the fact that it isn't web based.
     
    Last edited: May 31, 2009
  2. Diana

    Diana Approved members

    Joined:
    Aug 23, 2006
    Messages:
    1,565
    We are currently using the Dexcom and I just had to agree that it is irritating that the range on the graphs is from 40-400. I wish that were adjustable somehow. I also wish you could scroll through the older data points.
     
  3. MReinhardt

    MReinhardt Approved members

    Joined:
    Dec 29, 2007
    Messages:
    2,953
    Thank you for your take on both the Dexcom and the Guardian. I could not have said it any better on either one of these products.
     
  4. hawkeyegirl

    hawkeyegirl Approved members

    Joined:
    Nov 15, 2007
    Messages:
    13,157
    Thanks for posting this! It's as I suspected - they all have their pluses and minuses, and there is no clear "winner." Otherwise everyone would be using that one!
     
  5. Budapest

    Budapest Approved members

    Joined:
    Nov 29, 2006
    Messages:
    653
    Thanks for sharing. We were just thinking about ditching the Guardian after two years for the Dexcom. I assume you are writing about the SEVEN PLUS, right?

    The lack of memory in the sensor and the lack of ability to scroll through data history are a real bummer.

    I also got the impression, that the Dexcom doesn't have predictive alarms (low/high predicted) either. It has rate of change alarms instead -- is that just as good?

    Thanks.
     
  6. ecs1516

    ecs1516 Approved members

    Joined:
    Dec 11, 2007
    Messages:
    7,028

    It seems to catch lows as good as the Navigator did with its predictive alarms.
     
  7. someone

    someone Approved members

    Joined:
    Feb 9, 2007
    Messages:
    126
    Yes, it was the seven plus. Personally, I'm not as concerned with alarms as other aspects. I'd be happy if the thing didn't have any alarms, but I see where the predictive alarms may come in handy for younger children.

    Rate of change just tells you when your BG starts changing at a certain rate. You'll have to use this information to predict the high/low on your own because regardless of what range your BG is currently in, the alarm will be triggered if your BG starts moving rapidly. To me, this is more informative than the high/low prediction. After all, food and insulin aren't factors in the predictive alarm equation. But then again, alarms will likely be much more frequent if you have lots of BG swings and if your BG is moving steadily but not rapidly, the alarm will not be triggered. Keep in mind that I don't actually have experience with these alarms, this is just the way I see it.
     
  8. stevecu

    stevecu Approved members

    Joined:
    Jan 14, 2008
    Messages:
    403
    Something to keep in mind. The MM doesn't actually stop giving you data altogether if you can't calibrate within the 12 hour time frame.

    What I've realized recently is that while it stops estimating and graphing your BG, it continues to update the ISIG. While nowhere near as useful of convenient as the calculated BG estimate on the graph it is invaluable for figuring out whether your leveled off enough to calibrate. If you have access to carelink you can also look up the most recent calibration factor, and multiply it by the ISIG manually.

    What I've done a few times lately is, rather than calibrating at a questionable time just because the sensor is about to stop giving readings, I just ignore the Meter BG Now alarm and let it stop. When I think he's stabilized I'll upload to carelink and look at the last several ISIGs to determine whether I can get a useful calibration.

    It ain't perfect, but it's better than poisoning days worth of data with a poor calibration.

    Now if MM would just explain whether it's possible to purge a bad calibration without physically disconnecting the minilink from the sensor ...
     
  9. hawkeyegirl

    hawkeyegirl Approved members

    Joined:
    Nov 15, 2007
    Messages:
    13,157
    Steve, we also use the ISIG to keep an eye on things when Meter BG Now comes at a bad time. It actually works pretty well.
     
  10. someone

    someone Approved members

    Joined:
    Feb 9, 2007
    Messages:
    126
    I think it's a little ridiculous to have to do that manually though. What I did with the minimed when the meter BG came at the wrong time was calibrate with a value that followed the trend. That worked very well most of the time.. much better than using a fingerstick test to calibrate.

    That said, the Minimed does give you the ISIG/raw measurement, which is something I haven't found on the Dexcom.
     
  11. someone

    someone Approved members

    Joined:
    Feb 9, 2007
    Messages:
    126
    I have a little update to this.

    I'm back on the Minimed for a couple reasons. First, Dexcom just wasn't as accurate as I had originally thought. I can now say with 100% certainty that I get much better results with Minimed, but this may vary depending on the person.

    The other issue was the Dexcom sensors having an indication for 7 days. I never was able to get 7 days of good data from a sensor...nothing close. With the Minimed, I usually get more than I was able to achieve with the Dexcom. Given this difference between how long the sensors lasted, the Minimed sensors are MUCH cheaper. Essentially, you are paying for that 7 day indication as oppose to the 3 day indication that Minimed has. If your insurance is covering the sensors, you might not see this as an issue until you are unable to make it through the month on 4 sensors. One bad insertion and you can't use your CGMS for a week! A month's supply of Minimed sensors (10 count), usually lasts me up to 2 months if I use my CGMS all the time so I don't have to worry as much about bad insertions, etc.

    Just thought I'd share. Hope this is helpful.
     
  12. sammysmom

    sammysmom Approved members

    Joined:
    Oct 30, 2005
    Messages:
    1,635
    I wonder if the whole thing comes down to body chemistry. My son has been using the dex for a while now and it has brought his a1c down substantially. We check blood sugar only 2-3 times a day now. We tried all of the cgms and found the dex to work the best for our son. I am glad that you found a cgm that works for you. In the end that's all that matters!
     
  13. ecs1516

    ecs1516 Approved members

    Joined:
    Dec 11, 2007
    Messages:
    7,028
    I think it is body chemistry too. My older son can always get 10-14 days out of the Dexcom sensors.
     

Share This Page

- advertisement -

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice