Welcome to the DexCom Seven Plus


First off, thank you to everyone who responded to my call for ideas for new diabetes educational tools. I’ve got some follow-up thoughts that I’ll write about soon. But first, I need to dedicate a post to the newest member of my diabetes management team — the DexCom Seven Plus Continuous Glucose Monitoring System. To the sensor currently residing in my stomach: welcome.


As I’ve written about previously, I used to be on the Abbott Freestyle Navigator CGM, which I loved  — despite the fact that its adhesive was crappy and its transmitter was approximately the size of a VW bus. But alas, as anyone who’s followed CGMs in the past year knows, there’s been some problems between Abbott and the FDA, and they’re not shipping out any new transmitters or receivers — which is a problem since both of mine broke while I was traveling this winter. After some hesitation, I eventually took them up on their offer for a $2,000 rebate for the receiver/transmitter, and a refund for unused sensors (neither of which I’ve received yet). I was disappointed: I liked the system, but diabetes is every day, and I didn’t want to keep waiting. Plus, the CDE who’d originally recommended the Navigator said that in the years since I got the Abbott CGM, DexCom had actually jumped to the front of the pack.


After a bizarrely easy insurance approval process (at least I *think* it was approved — I’m on a high deductible plan so at the moment it’s out of pocket), my new system arrived on Friday and I’ve been wearing it for the past few days. So far, so good — but there are definitely some features of the Navigator that I wish that the Seven Plus had as well. Here are some preliminary thoughts — feel free to add your own:



-the size of the transmitter. If the Abbott was a VW, this is a Vespa. Better than car analogies, here’s a photo:

I do wish that the receiver itself were smaller — there’s a lot of extra space that’s not being used for the screen. And I’m not sure why the adhesive patch is so big. But the transmitter is the smallest of the three companies’, and I appreciate that.



-Speaking of adhesive: it stays on! I cannot begin to express how crappy the Abbott adhesive was. Even with no exercise, it wouldn’t stay on my stomach for more than a few hours without needing to be reinforced with an obscene amount of IV prep tape — adding to its ugliness and conspicuousness. I’ve had the DexCom on since Friday (three days) and have worked out hard twice and taken three showers. It’s also on my stomach in an area that bends if I’m doing sit-ups (whoops). So far, it’s not peeling at all. The material is fabric-y, similar to the adhesive used by Minimed pumps. Such a relief.



-the sensor life. Seven days? (With the potential to go off label and wear it for longer?) When you’re talking $60-$70 a sensor, that’s a big deal!



-readings every five minutes. That might sound like a strange pro, given that the Abbott gave readings every minute. But you know what? I think every minute is too much — it makes you too likely to overreact to a changing number and stack insulin. I’m pretty sure that’s part of the reason I had some of my worst lows right after getting the Abbott.



-an effective snooze feature. The Abbott was constantly beeping and vibrating at me, regardless of how I adjusted it, and would continue to beep/vibrate till I attended to it, like a crying baby. The DexCom is like a well-behaved ten-year-old: you explain that mommy is in a meeting right now, and it shuts up. You can set the snooze for anywhere from a half hour to several hours. (Okay, maybe not *exactly * like a ten-year-old.)



-less lag time. If the sales rep I met with is right, its numbers are supposed to run only 5-10 minutes after your actual blood sugar, as opposed to the Abbott, which was at least 15 behind.



-There’s more subtlety in the trend arrows. The DexCom can be set to alert you when you’re rising/falling by 1 mg/dl, 2 mg/dl or 3 mg/dl per minute — which is helpful in determining just how much to freak out!



-It’s comfortable. I found the Abbott comfortable, too, but just in case anyone’s worried about how the sensors feel — I really can’t feel them at all.


-You can shut it down temporarily — great for situations when you REALLY don’t want it to go off. It also seems like there isn’t a risk of hitting the wrong button and ending the sensor session by accident, which was a very annoying and expensive limitation of the Abbott.



-You can calibrate when your blood sugar is moving. Which brings me to . . .



-2-hour calibration time! How could I have forgotten that till the end! The Abbott was 10 hours.



Cons (or, to put it more productively, “suggestions for improvement”):

-There aren’t enough numbers. The only number available on the receiver is your blood sugar right now, but you can’t scroll through past blood sugars. This is a major inferiority to the Abbott, which allowed you to scroll through your numbers in increments of say, every ten minutes, every half hour or every hour. With the DexCom, there’s no way to tell exactly how high (or low) I got last night when I was asleep — especially since the trend graph goes all the way from 40 to 400, which makes it really hard to get a subtle view of past levels.



-Similarly, there are no hours on the trend graphs. There are lines indicating hour markers, but no numbers, so it takes a bit of figuring to determine what time particular events happened.



-When you enter events, they don’t appear on the trend graph. What’s the point of entering the  events, then? I want to be able to look at the graph and determine say, how long it took for that insulin dose to take effect, or what exactly happened during/after my workout. Very annoying. I’m guessing that there’s some way to see them using the software (and maybe get more numbers, too), but I don’t know, because the Data Manager software isn’t compatible with Macs. Which leads me to . . .



-The software is not Mac compatible. Come on, guys! Abbott’s wasn’t either. In this age of iPhones, I think they’re really leaving out a large percentage of users by not making a Mac version. This is especially annoying given the limitations of the data displayed on the receiver.



-Back to the receiver . . . you can’t scroll back through time. Yes, I know, you can look at the trend graph in 1-, 3-, 6-, 12- or 24- hour views. But say I want to scroll backwards in one-hour chunks so I can get a more detailed view of my morning. Can’t do it. I have to use the six-hour view, which scrunches the graph up and makes it even harder to read, especially since there’s no way to see exact numbers. This would be a bit better if there were a way to set a target glucose range, as you did on the Abbott, where you can see a gray bar indicating the range that you’re trying to achieve. But unfortunately . . .



-You can’t set a target glucose range that’s separate from your “high” and “low” alerts. On the Abbott, I was able to say that I wanted to have a target, say, of 80-135, and then two dotted lines would show up on the graph that helped me determine how much time I spent in my target, with a gray bar in between — very easy to read. My “high” alert was separate, and wasn’t set to go off till 160. On the DexCom, on the other hand, the two are the same, which means that it’s currently beeping at me any time I hit 140. Especially given the other limitations of the trend graphs, I think it’s important to allow people to set a target range that’s separate from the high and low alarms.



-High alerts go up in increments of 20 mg/dl. Why? In other words, I can get a high alarm at 140, 160, or 180, but nothing more subtle. Low alerts, weirdly, go down in smaller chunks. Why not make that entirely customizable? I want to stay between 80 and 135, and I want my high alarm to go off around 160, but I can’t.



-The beep isn’t quite loud enough to wake me up. I guess that’s where Abbott’s “crying child” feature comes in handy.



-There are no predictive alerts. Other bloggers have pointed out that the additional trend arrows (the 1 mg/dl, 2 mg/dl and 3 mg/dl per minute ones mentioned above) cover this, since if you see a double arrow headed down, you probably should pay attention. But then again, maybe not: if I’m correcting for 300, and I start dropping 3 mg/dl, that’s cause for celebration, not alarm. I’d like some predictive alerts.



-the battery is rechargeable. That’s a good thing in some ways — saves money on those triple As. But it means it only lasts for 3-5 days, instead of several weeks, and if you forget the charger and go out of town, you’re screwed. Also, the transmitter battery is built in, so once it dies, you have to buy a new one. I’m not sure how long they last or what insurance coverage is like for them — perhaps other users have more info on this.



-as a complementary issue, the range of the transmitter is very limited — like, five feet, as opposed to the Abbott, which could pick up a signal from a different room in the house. I suspect that this is related to the small size of the transmitter (you can’t have everything). But still: annoying. Especially since if you’ve got it plugged in to charge, you have to stay pretty much right next to it if you want it to keep picking up readings — and they don’t recommend that you keep it plugged in overnight.



-it has to be calibrated at least once every 12 hours. I actually don’t mind this too much, since I’m always double-checking on my meter anyway — but I could see people finding that annoying.



So those are my, uh, initial thoughts (I didn’t realize they’d be so long). Basically, there are a lot of aspects of the DexCom that are more convenient and comfortable, but I find the information displayed on the transmitter to be much less useful than the Abbott — which is a major downside (especially with no software that will work on my computer). It’s almost like the DexCom promotes a Buddhist approach to diabetes: live in the moment and don’t dwell on the past. Unfortunately, that’s not exactly how my attitude toward diabetes works — I want to be able to ruminate! I need data points!



But even with its downsides, I’m thrilled to be on a CGM again. It really does make a difference, and I can’t wait to see what the next generation might be like.

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jual gamat
7 years ago

Excellent summary of the Dexcom, Catherine! I recently switched to the Dexcom Seven Plus from the Medtronic Real Time CGMS. The Dexcom is far more accurate (consistent with BG values). In my experience, the Dexcom has tracked close to BG, even during times of rapid change. No real lag issues like the Medtronic. I really miss the convenience of having my CGMS display on my pump. But, accuracy trumps convenience big-time in my book! I concur with your comments on the Dexcom receiver. It is really bulky and provides very little in the way of diary review capability. This limitation… Read more »

9 years ago

I have not been impressed with mine, had it for 6 months and finally quit using it due to the wildly inaccurate readings I get and their terrible customer service. If you want to get through to someone in sales it’s no problem but if you want help, leave a message and wait for 2 or 3 days. I think a class action lawsuit against them is inevitable unless they get their act together.

10 years ago

Robert – Hope you will update your site because Friday, April 27 i just received my Dexcom 7 and thought i could do everything myself with getting started but after reading, boy i think i need some help.  I have trouble with severe low’s under 30 and hope that this will be able to better track my lows.  It’s been wonderful being able to read everyone’s reviews.  I previously read that some people were using there arms instead of their stomach.  I currently use by stomach ares for giving myself Humalog shots throughout the day.  I was curious if there… Read more »

10 years ago

I just purchased mine which my insurance (United) surprisingly covered and submitted for a $200 rebate which I just received today!

Teri Spivey
11 years ago

Catherine, your assesment of ths Dexcom 7+ CGM was dead on!! It is my belief that the Dexcom CGM is truly the best on the market, and my dealings with the company on every level (from education to customer service & support) have been exceptional. I have only been wearing my Dex 7 for 2 weeks now, but have had the chance to compare it to the Medtronic CGM (which BTW I hated!) and it has become my best friend! I am a Type 1 diabetic that is in the “honeymooning” phase, I sporatically produce insulin which combine with the… Read more »

11 years ago

I feel your pain, RLL. My receiver received irreparable water damage after a month and a half, and now I am back to sticking my fingers, because I refuse to pay the “goodwill” price of $299 in full for a replacement – I could barely afford the system to begin with (and I have “good” insurance). I am frankly sick of the whole idea now and find it hard to believe that we live in the most prosperous nation in the world – I work full time and pay my bills but as a diabetic I receive substandard care because… Read more »

11 years ago

RLL, The Medtronic sensor is very, very painful to insert.  The tape and sensor caused skin irritation and the IV adhesive allows water to seep in and soften the skin.  I have a DEXCOM for a trial and it is much better.  Sorry to hear the receiver dies so quickly with it being as expensive as it is.  I probably won’t buy it now.  Good luck finding another sensor but I do NOT recommend the Metronic Real Time sensor.

11 years ago

This is the first CGM i have had. I got it in December of 2009, that receiver lasted until September of 2010, and like Hallie it was replaced quickly, however, that receiver died today, 8 months later. DEXCOM is refusing to replace it because of the 1yr. warranty, which they say was “up”  in December of 2010, which was on the original receiver..not the replacement receiver.  They take the warranty from the date of purchase, not the date of the replacement. They offer a 1 year warranty, but their receivers only last 8 to 9 months.  I am seriously looking at all the options… Read more »

11 years ago

I have 2 kids using the Dexcom. I think you are very on point. I would add tho that the more out of range the actual bg is, the less accurate the Dexcom is. We have seen wild variations. And way too many sensor failures. In my opinion it’s the best CGM we’ve got, but there is lots of room for improvement!

11 years ago

Excellent summary of the Dexcom, Catherine!  I recently switched to the Dexcom Seven Plus from the Medtronic Real Time CGMS.  The Dexcom is far more accurate (consistent with BG values).  In my experience, the Dexcom has tracked close to BG, even during times of rapid change.  No real lag issues like the Medtronic.  I really miss the convenience of having my CGMS display on my pump.  But, accuracy trumps convenience big-time in my book!  I concur with your comments on the Dexcom receiver.  It is really bulky and provides very little in the way of diary review capability.  This limitation… Read more »

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