Why I'm Giving Up on CGMS

[Funnygrl]

http://img100.imageshack.us/img100/8012/img0155ff6.jpg

http://img215.imageshack.us/img215/5526/img0157tx7.jpg

And it continues like that, all night, every night, alarming every 25 minutes.

[statdeac]

What the heck? I hope the Navigator is better than this. :s

[Alice]

I talked to my doctor about some of the problems with "accuracy" that I have been hearing...she looked me square in the face and said "NO, they are very accurate."

I told her I would like to wait for the next few generations to arrive before I invest all that money. I do have hope for the future with this technology, but I wonder if they went on the market too soon.

I wore the Guardian? a couple of years ago when they first were being used by doctors. It was a 3 day test. She didn't like the numbers...I went home and analzyed my logs vs her printout. There were a lot of 50+ differences. (She didn't want to hear it)...also, I had to repeat the test since they tech had switched the Am/Pm setting my first day. That's not a biggy, but I found the overall training lacking with the doctor's office.

[BlueSky]

... And it continues like that, all night, every night, alarming every 25 minutes.
Maybe I am missing something, but isn't this what it is supposed to do? Those BG readings are low. Or is accuracy the issue?

[notme]

I think it is the accuracy issue she is complaining about Bluesky. Her meter is reading 97 and the CGMS has her in the 40's.

I am waiting for a more simplistic and accurate CGMS as well.

[Funnygrl]

Maybe I am missing something, but isn't this what it is supposed to do? Those BG readings are low. Or is accuracy the issue?
Yes, it's suppose to alarm, if I'm actually low. It's not suppose to alarm if I'm 97 cause it thinks i'm in the 40s.

[NoelD]

I see it all the time if I use the Freestyle meters. On the other hand, I noticed that it tracks very close to the OneTouch meters. Someone has noticed the same thing if I am not mistaken.

[Alice]

So, are the FreeStyle meters "off" or is it the CGMS?

[Funnygrl]

I see it all the time if I use the Freestyle meters. On the other hand, I noticed that it tracks very close to the OneTouch meters. Someone has noticed the same thing if I am not mistaken.
I've tried the Ultrasmart also, and my Ultrasmart reads the same as my Flash.

[Cyborg]

Thus, the reason I gave up on Dexcom. I was seriously considering switching pumps just to go with the combo pump/cgms from MM. Problem is that I really want some of the features that only the Cozmo has and now I see this. I think I'll wait...

[RobiJo]

How frustrating for you! I've had days like that but not too many. I'm usually pretty accurate (within 20) between my Flash and sensor. I noticed when it's off by more it happens after I have to calibrate at a bad time. I tend to calibrate when I wake up, but if I'm low and have to ENTER BG NOW, but also need juice to get in the car and drive to work....my bg has raised before the calibration took full effect and then it's off a bit more and I get readings like your picture.

Like I said though, most times I'm within 20. I do look forward to the day that this is more accurate and dependable. It sure would be nice to be able to trust it completely! Though the same could be said for meters in general as well.

[Cyborg]

Though the same could be said for meters in general as well.

I absolutely trust my meter. I, in no way, trusted my CGMS...

[Funnygrl]

I absolutely trust my meter. I, in no way, trusted my CGMS...
Same exact thing here.

[birds_eye]

Hey funnygirl I had this same problemmo - my cgms going off every 25 minutes during the night was crazy and what was even more frustrating was it's accuracy compared to my One Touch Ultra! :stupid: Going through all this mission of wearing a cgms attached to me like a 6th limb, the stress (for me) of application and then ultimately getting inaccurate readings. Urgh.

I am however quite excited for future products. A slim line nano like cgms that reads every 5 minutes and even plays mp3!! haha :rock:

[Dewey]

Funny, sorry to hear the sensors aren't working right for you. :( I'd hate being awakened by alarms if they weren't accurate...

That said, I still question the validity of both the sensors & the meters. I don't feel that either are 100% accurate. I've known the Freestyle meters to read higher than my UltraSmart, but there have been times when the levels were quite off. I've had readings on one of my Freestyle Flashes that were 100 points off one or two times. When in doubt, check with another meter (if & when possible).

Again, sorry to hear about the troubles you've had. :( Hopefully in the near future, we'll see more & better advancements in this area.

[condensr]

Yep, they can all be pretty off.

Heck, tonight my sensor was reading 190. I tested with my Ultra2, and it said 285. I checked again immediately with the ultra2, and it said 322. I tested a third time, and it came up 302. I chose to beleive the 302, but the correction for that was wrong. I ended up going low.. Shoulda beleived the 322. Ugh. Yes, those are high numbers.. Think I'm fighting a bug as I've been seeing numbers like that since yesterday with no change in patterns on my part, food or insulin wise that is. Blech. Its like my carb ratios suddenly just dropped substantially.

[Alaska]

Another thing you have to think about is where is the blood for the testing coming from? If your not using the same blood your tests are going to be off. I can poke one finger and get a reading and poke the finger right next to it and get a completely different reading with the same meter and strips.
IF it were me I'd wait to see what my A1C said. That's the true test of how accurate that metering is.

[condensr]

In my case, it was the same finger, same poke. Had just washed my hands.

[Alaska]

In my case, it was the same finger, same poke. Had just washed my hands.


You had the sensor on your finger?
What I am saying is two different parts of the body will definately give you two different readings. Even fingers next to each other will differ Area's with high blood flow will give you a far more accurate reading because the heart is pumping blood to the area. Fingers tips are a high blood flow area due to the fact that it needs to flow quickly to keep you warm. A reading saying coming from a sensor on the stomach will has less blood flow therefore less of an accurate reading
That's just a wild guess though but I made sense to myself LOL

[Tony]

Yes, it's suppose to alarm, if I'm actually low. It's not suppose to alarm if I'm 97 cause it thinks i'm in the 40s.
We all are forgetting one very important factor and that is, the cgms reads glucose in interstitial fluid(ISF) and a glucose meter reads glucose in the blood so your readings will be different.

Glucose moves first from blood vessels through the ISF, then into cells. The glucose present in ISF is normally about 20 percent lower than glucose in the blood. ISF glucose falls earlier and rises later than blood glucose.

[Funnygrl]

We all are forgetting one very important factor and that is, the cgms reads glucose in interstitial fluid(ISF) and a glucose meter reads glucose in the blood so your readings will be different.

Glucose moves first from blood vessels through the ISF, then into cells. The glucose present in ISF is normally about 20 percent lower than glucose in the blood. ISF glucose falls earlier and rises later than blood glucose.
I had been testing all morning though, and I was never low. So it wasn't just a lag.

[duck]

I'm sorry you've had such a bad go with this...with the exception of maybe three or four days since late July, I've had real good luck with these things.

[modbom]

The regular meters are required by the FDA (in the US) to be off by no more than 10% (of what, is not specified) the CGMS is much less accurate than even that relatively low standard. Here's a link to minimed's manual. choose the one titled MiniMed Paradigm 522/722 Sensor Features Guide. Once you've downloaded it, scroll down to "Accuracy" User Guides (http://www.minimed.com/products/insulinpumps/userguides.html)

I just got approved for one by my insurance company but have great trepidation about using something that is particularly inaccurate during highs and lows (as shown in their charts)

[Dewey]

The regular meters are required by the FDA (in the US) to be off by no more than 10% (of what, is not specified) the CGMS is much less accurate than even that relatively low standard. Here's a link to minimed's manual. choose the one titled MiniMed Paradigm 522/722 Sensor Features Guide. Once you've downloaded it, scroll down to "Accuracy" User Guides (http://www.minimed.com/products/insulinpumps/userguides.html)

I just got approved for one by my insurance company but have great trepidation about using something that is particularly inaccurate during highs and lows (as shown in their charts)

From my understanding, regular (BG) meters are allowed a 20% margin of error. To me, that's still quite high. As far as the CGMS goes, I can't speak for everyone else as each of us will have different experiences, but I've found it to be quite on the mark most of the time. Even when it's off or lagging behind the meter, it's been by about 10 to 20 points, max, and that's usually when there's a rapid change in glucose (i.e. BG is going up or down quickly).

Not sure what's happening in Funny's situation, but I sure hope something gets figured out soon. I wonder if MM wouldn't be willing to give a loaner pump/CGMS or even a different transmitter to try & troubleshoot the issues she's experiencing. :(

[JediSkipdogg]

Dewey got it partially right, that's actually the old standards that lasted for about 20 years (FYI I didn't know what I'm about to say.) In 2003 they partially updated ISO 15197 (International Organization of Standardisation) to tighten the requirements.

Prior to 2003 GLUCOSE (key word there) had to be within 20 mg/dl for any reading under 100 mg/dl and withing 20% for any reading above 100 mg/dl. In 2003 they reviewed and tightened the levels some. However, tightened is far fetch in my opinion. They redid the standard to meters must be withing 15 mg/dl under 75 mg/dl and withing 20% for anything over 75 mg/dl. Those standards are based on comparing a self monitoring blood glucose (SMBG) device with lab reults.

Now, here's the problem. There is no standard yet that must be met for anything reading instertitual fluid (which is what all current CGM devices read.) Therefore they can legally/technically be off whatever percent they want. However, logic says the more they are off, the less people will buy them. Therefore both Dexcom and Minimed are using the above ISO standards except they are using the calibration point as their reference point. Therefore if you are running say 100 by lab standards, you can technically get a 115 by your BG meter and the CGMS can read 130 and all 3 numbers would be within "standards."

Now, let me throw something out there for all to think about. Which is more precise to what your body is? A CGM measuring interstitual fluid or a BG meter measuring blood? Blood is simply a carrying path of glucose into the cells pushed by insulin. The CGM is a measure of what's around the cells. Therefore if one is running 500 mg/dl by a BG meter, they may only show 200 on a CGM and in my opinion, that could be perfectly normal if the glucose hasn't made it from the blood to the interstitual fluid yet. I'm currently trying to research more into that but it appears there haven't been any medical journals for that topic yet.

[Funnygrl]

The problem is, a lab will measure glucose levels in the blood. Therefore, blood glucose levels are calibrated to just that- blood.

If we wanted to switch to an interstitial standard, we'd have to re-define normal.

[JediSkipdogg]

The problem is, a lab will measure glucose levels in the blood. Therefore, blood glucose levels are calibrated to just that- blood.

The real problem is labs measure the plasma in the blood. BG meters can't seperate plasma out therefore they measure whole blood and convert to plasma. Which may not be accurate since there are other components in whole blood besides just plasma.

[KEVIN88GT]

so I'm fighting tooth and nail with my insurance company to approve me for the CBGM and they are that innacurate? Are there others here that have GOOD results with this technology?

[JediSkipdogg]

so I'm fighting tooth and nail with my insurance company to approve me for the CBGM and they are that innacurate? Are there others here that have GOOD results with this technology?

Some have good days some have bad days. Some users have a great time wiht it, some have no luck at all.

The product is a first generation, and therefore it's full of accuracy flaws which is why the FDA won't approve them as a "replacement" for fingersticks yet. And that one word is what is holding insurance back the most. As they would rather pay for 10 strips a day than a sensor and 10 strips, since one technically can't use the logic of testing less with it.

[KEVIN88GT]

why cant you test less with it... I thought thats the whole point..... getting testing down to the 3-4 times you have to calibrate the unit.... instead of the 10+ sticks

[JediSkipdogg]

why cant you test less with it... I thought thats the whole point..... getting testing down to the 3-4 times you have to calibrate the unit.... instead of the 10+ sticks

You still have to use a fingerstick before you give any insulin injection, which would be any meal you eat. Anytime you think you are high or low and the CGM concurs or is off you have to do a fingerstick. Right now, the CGM is only classified as a supplement for fingersticking regardless of what people say. That's how the companies have to market it and that's how insurance looks at it. And for their inacuracies (which may be rare) relying on them once when it's wrong and making the opposite choice could lead to a very deadly incident. Nothing like the CGM telling you are 200 and you inject enough insulin to bring it down to 100 and you are truely running 100.

[BriOnH]

FG, Cyborg, thanks for the info. I really want one, but lag time was my biggest pet peeve. If accuracy is that far off that pretty much puts the last nail in the coffin for now.

2 opinions I know are very credible says it's a no go for me. Unfortunate.

We need cells to read our glucose levels. Not machines :( .

[Funnygrl]

Kevin-

You can test less at all. I'm averaging around 13 tests/day right now. I'm doing my regular ones I was doing pre-CGMS: before and after meals, when I wake up, at bedtime, before driving, before and after gym, and sometimes in the middle of the night.

However, I've had to add testing anytime it says I'm low or high. With some of the inaccuracies I've had- that can add a lot of tests a day.

One day I tested 22 times. While I realize it sounds insane to test just cause the sensor says you're 40 when you KNOW it's been running low, it's very hard to just ignore a thing alarming because it has reason to believe your bg is in the seriousy-low zone.

I took like a 2 week break from it and started again a few days ago. I'm on day 4 on this sensor, and it's been extremey accurate so far.

[modbom]

thanks for the clarification JediSkipDogg. I wonder if folks who are getting better results with the CGMS are doing something different:
calibrating with fingersticks more or less often or at different times?; eating less carbs?; in tighter control to begin with? I'm working as a roadie these days- waking up in a different city every day, 16 hr work day, sleeping on a tour bus at night. It'll be exciting to adjust to this new tool under those circumstance.

[Dewey]

I must say I've been overall pleased with mine. I'm not sure why some do well with the CGMS & others have issues with its accuracy, but I've personally been fortunate. Sometimes, the CGMS has been right on the money in terms of accuracy, and other times, it's been off (in which case, I do a BG test to confirm one way or the other). I have been able to test less on some days as a result of this, but being the control freak that I'm known to be, I like testing as often as possible anyway. I never intended this item to be a replacement to fingersticks, and until the overall accuracy is worked out, nobody should.

[Funnygrl]

I'm trying again today- I'm int he 2 hr warm up period now. We'll see how it goes.