After what I feel has been a very fair and open trial with the Dexcom meter I have finally given it up. I gave it about 7 weeks total.

I look forward to reactions to this article. My personal opinion is either I am totally unique or something is amiss with the product function.

FOR ME ( and I emphasize that, as many of you may use the product and really like it ) the meter has been so innacurate so many times that I can no longer trust it.

Here is my Dexcom story. This may ruffle a few feathers and I apologize if it does but I believe that my story has to be told. I cannot be the lone ranger. If I am I would really like to know why.

For the Dexcom folks who will probably read this as well.

1. I was not on any Tylenol based products
2. I had reported to Dexcom on several occassions my frustration.
3. I did not enter measurements into the Dexcom unless it was over 20% off.
4. I always entered measurements when the meter asked me to.
5. My ultimate response from them has been -
- it is best used for trending
- we really can't explain why your results are off by so much.

History - I was diagnosed in 1998 with Type II. I was 49 years old. I am now 63. Over the years my A1C has risen gradually to a point where it is now 9.6 and a constant struggle. I am not overweight nor have I ever been. I eat healthy for the most part. I have never been interested in fast food and buy organic when I can afford it and don't eat much where I can't define even one of the words in the contents description.

I am also a heart patient, which complicates things even further. But that is another story I am going to post.

I was EXTREMELY excited when I learned of the Dexcom and how it might help me. I could actually judge the effects that certain foods as well as excercise had on my system.

From the beginning I have operated on a couple of assumptions.

1. The meter should basically be within 20% of your actual
2. If you use it as a trending device, helping you know when you are going up or down, it iwll be more successful.
3. Dont take any Tylenol.

Initially I thought that it would be fairly accurate, at least something I could depend on to keep me in the know if I was moving toward a crash. We all know how much fun crashes are. And they sneak up on you as we also all know.

My first bad experience came in my first week of use. It was 10PM at night and I was sitting on my couch with the meter on. It read 135. l started to feel the symptoms we all recognize so I tested my blood sugar and it was 35. Not only was it off by 100 points, I was home alone with a serious crash. What if I had gone to bed thinking I was within range?

I continued to use the meter as prescribed for several weeks. With so many errors and complaints to Dexcom they had sent me 2 extra sensors for free. So six weeks goes by. I use the meter. I am still surprised on a regular basis on how far off it can be. I stopped for a couple of weeks just to see how I would feel about going back to the old way.

After a week or so, I finally decided that it in fact was more help than harm so I took it up again. I had used up my last sensor so had to wait to get new ones shipped. This time I decided to track more closely my meter against the Dexcom.

In the space of a week it was off more than 30% multiple times. In one instance my blood sugar went from 103 to 45 in a 3 1/2 hour period. But the Dexcom did not tell me anything. The Meter register 103 when I was 70 so I did a reset by entering my blood sugar. That took the meter to 91 for the adjustment. This was at 5PM. At 8:30 PM I did another test as the meter said I was 72. I was actually 45. So the main overall experience was a meter reading of 103 with a Dexcom reading of 70, and then a meter reading of 45 and a Dexcom reading of 72.

As a result I was testing my blood sugar all the time to make sure the meter was functioning. That does not help anyone.

AT this point in time I no longer feel that I can trust the meter to tell me anything as I always have to question whether I am getting reliable information

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Completely understandable reaction to the situation. If it doesn't work for you, there's no reason to use it.

Here are some additional things that I had to figure out on my own.

1) If I didn't give a newly inserted sensor time to settle in, nothing I did mattered. For me, that meant that I let my senor sit over nighte before I would even think about trying to calibrate.

2) The longer the sensor was in, the more stable and accurate it got. Although Dex says it's only good for a week, if you go to the Dex forum, you'll see some users seeing the sensor lasting way beyond the 7 day mark. I think the longest I saw was 21 days. If a sensor didn't last at least 7 days, I was dissapointed, and mine generally lasted beyond 10 days. The most accurate and stable readings would be in the last few days before the sensor finally crapped out.

3) Placement, placement, placement. Some sites were just better than other sites. People have found some pretty interesting places to put a sensor to get good readings.

4) Sometimes, it just doesn't matter.Yup. Some sensors just returned craptacular numbers, period.

Again, no need to aoplogize for anything if something just doesn't work for you.

Oh, and when I say "On my own", I mean independent of help from Dexcom. Our own Dexcom users group here ha been a wealth of information and I doubt I could have managed without them.

I agree with FHS, yours is a totally understandable reaction to your situation. Some things work better for some people, and some don't, we each manage our diabetes in the best way that we can and use the tools that work best for us. And the CGM technology is definitely not perfect yet. At least it's a step in the right direction, though. Adding to FHS's list of things, another thing I had to learn was that the sensor has a 10 to 15 minute lag from a regular finger stick because it's reading from interstitial fluid and not blood. 10-15 minutes is a long time for me in my world of diabetes. So, for example, if I looked down at my dex and it read "80" with an arrow point slightly down, I finally figured out "crap, that means I'm probably low already". When I go low I tend to drop REALLY fast, so when the dex says "80" I'm usually much lower already. I ended up setting my low alarms a little higher to help me catch that. Anyways, thanks for sharing your experience! I love this site because every time someone shares how things worked for them it helps someone else out in some way. I've definitely benefitted from other people's reviews of diabetes products.

Yes, I agree with Erin. I had to learn how to use those arrows as just a sign of when to fingerstick. 80 and a slight arrow down could mean 57 or it could mean 77 or it could mean 107 but I learned to read it as dropping so check. I also ended up setting my low alarms as high as they allow. But as she said, we all find what tools work for each of us.

I understand your frustration and I'm sorry you've had a bad go of it. The technology is just not where we'd like it to be yet. For me the good outweighs the bad. I am hypo unaware so in this sense the Dex has been a blessing for me.

The number may be off sometimes but the arrow and the alerts always let me know what direction I'm headed so I can fingerstick more often if I need to. I have an alert set to let me know if I'm coming down fast with one or two arrows.

I've only been using the Dex since September and when I first started with it I was under the impression that I was only going to have to test with a fingerstick twice a day to calibrate the Dex. I was disappointed when I found out that it was actually more work than I was doing before. But my control has also improved.

For me, the Dex and eating low carb have stabilized my levels and I'm expecting lower A1cs. I've found the more I'm in target range the more accurate the numbers are. I've also found through trial and error the places on my body that work best - I'm currently on day 13 with a sensor on my arm near my shoulder and most of the time with this site the Dex reading has either matched my meter exactly or tracking it closely.

You're lucky that you still feel the symptoms of lows. I don't so the Dex is my security blanket.

I am very excited to see that people read what we write and comment. So thanks. I guess my concern is when it is 100 points off and there are no arrows telling me what is going on I "personally" lost faith. And as one of you said I found myself sticking myself many more times a day than without the meter because I did not trust it.

The stuff about the fluids being tested by the Dexcom and the blood being tested by the meter and the inherent delay is a great piece of advice.

Also using my arm instead of my stomach is a great suggestion as well.

I will have to give this a bit of thought but might run a second "trial" using these two suggestions and see what happens and if readings improve to a level where I can have more trust. As I said early in my statement the concept is very exciting to me as I often don't sense lows until I am in the 40's, which always means I am going to have an hour or two of really uncomfortable crap while my blood sugar comes back up from a sugar infusion of some kind.


Np Mark.

If you haven't had a chance to sneak over to the Dexcom group, it's a wealth of information. It's also a place where you will find plenty of people who will commiserate with you.

I agree wholeheartedly about the number of fingerstick tests as a result of using teh Dexcom. I test at least 10 times a day and may test up to 20 times a day. I thought the Dex would save fingersticks but I found myself doublechecking it's reading so much that I pretty much broke even. I will say that the ability to see trends, if it's working correctly of course, is invaluable in too many situations for me to name in this post. That was worth the price of admission for me.

Best of luck and keep us posted!!

I truly sympathis with your post.

Posts so far have done excellent job sharing data and thoughts but I would add the following:

a) using the dam sensor on gut for me was a total disaster. I use it on my upper arm. Others have other sites that work better than gut. ( readings on gut 160 and on fingertips 238) Other sites have reported same.
b) your caveman machine will always be ahead or behind the dexcom as it is interstitial on arm so with machine delay's and tissue delays one tends to get averaged waveform. During slowly changing BG values; I found that reading was surprisingly good between a freestyle lite and test strips and dexcom sensor to within +/-3 to +/-10 points.
c) on faster changes, caveman machine will always track faster than dexcom. On a fast change you will see readings 10 to 20 different at times as the dexcom is scrambling to catch up to fingertips.
d) don't retire the caveman machine yet and ensure you are periodically checking with it.

e) whose caveman machine are you using. Contrary to all the lies, only the free style lite and one touch are filtering and testing for only human glucose D. There are other machines and good ones whereby if I eat trick sugars in a food, 2 hours after eating, i will see wrong total blood sugar readings - Glucose D plus the crap. The lies peddled is that is not supposed to happen, bull s***, my system flings them around for a few more passes thru the liver to get out. Readings would be 20 to 50 too high on such machines. The One touch was too sensitive to water levels in my blood and kick off bad readings if my blood was not watered down all the way. Accuchek - nope forget.

When things are quietly stable and slow moving, I see very good correspondence between the Dexcom and fingerprick.
On the gut - forget that crap.

The simple answer is that Dexcom is probably accurately recording what it sees on your arms interstitial test point - not your fingers.

Hope this helps. Oh yes - watch out for receiver getting too warm as it can stall out on bad readings. Also, RF interference can also play similar tricks and Dexcom does not flag or report visually for user.

The dexcom probe is also filtered against trick and other sugars as well.

Lastly, report this to FDA and ignore those who say not to.

That is

Please tell me what trick is and what you mean by RF. And thanks for the rest. At least I am not alone in this.

RF is "radio frequency" - what wireless electronic devices use to communicate :)

I find that local rf - wireless servers for intermet, security camrera wireless units and assorted items like that will cause system to become unlinked and not communicating.

For instance, I was at dentists building where unit normally runs ok and suddenly the receiver went disconnected.

That did not stop even though I parked receiver right on top of the transmitter till I left and went out to my car - metal shell and units immediately connected and worked fine.

Issue - do not know - mayber diathermi machine using RF to heat body tissues or some other device.

I rarely have any issue working in my car driving all over Los Angeles but in buildings and in my condo building - always running into spurious disconnects. Unacceptable.

Driving up 395 highway behind sierra mountains to Bishop, everything behaves itself peascefully without any annoying hiccups.

So, without rf spectograph hardware usually used to track RF emissions for product approval on FCC and European standards, I really have no specific data. But I should not have to do that.

FWIW, I had a very similar experience with two different CGMs (Dexcom and the MM one). I really understand that they are for identifying trends and any high/low should be confirmed before treating it. In my case, I just found it too easy to look at the Dex and decide what to do, and this of course resulted in the improper treatment of some false highs/lows. For me, because I'm so active, I think that somehow interfered with the results. I don't know. Maybe my interstitial fluids are just off or something.

Either way, you have to keep in mind that this technology is evolving. I think think CGMs are amazing, and I sincerely hope they can improve them over time. For now, I'm not using a CGM. I use a pump too and I can't give up any valuable realestate (worried about developing scar tissue!)

stated excellenty, better than me and on target. thank you




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