How acurate is CBGT?

[Momof4gr8kids]

How accurate is countinous b/g monitoring? I have read over, and over that you still have to go ahead, and do a finger prick in the event of a b/g that is out of range. Is it not acurate? What is the variable?

[rickst29]

The FDA has, so far, refused to approve any CGM which claims to replace traditional blood glucose testing meters.

I hear that Abbott asked that the Navigator be approved as a replacement, and that's why Abbott's approval has been delayed for so long. I now hear that they're "backing down": they'll accept the limitation "confirm the Navigator reading using your blood glucose meter BEFORE treating", and then ask for the approval to be upgraded after it's been in the Market for a while.

Between the FDA and the 3 companies' own lawyers, who DON'T want to be legally responsible for mistreatment based on an erroneous reading from these less reliable machines, you get the "confirm before treating warnings.

My Dexcom manual (page 55) says, in a little black box,

WARNING

Symptoms releated to low or high blood glucose levels should not
be ignored. If you have symptoms of low or high glucose, use your blood glucose meter to sheck the STS System results.


It's not formatted like a genuine "Black Box Warning", as seen on "risky" drugs-- there's no bold type, it's just within a little box. But you're not "allowed" to use the Dexcom reading without confirmation.
- - - - -
What happens in the real world? For ME, Dexcom is so accurate that I've basically given up traditional testing: I only test when it demands a "calibration" measurement, or (once in a real long while) when I'm suspicious of the reading.

When I "extend the graph" forwards for about 15 minutes, because ISF readings are about 15 minutes "behind" blood readings, it's usually almost dead-on: within 10-15 points of my One-Touch Ultra bG meter. And 15 points doesn't make any difference in my treatment choices: if it says "75" and it was really 90, well, I should have eaten a bit of something anyway. If it says 55 and I was really 45, I'm already doing the right thing (6-8 sugar tabs). And if it says 200, but I'm "merely" 180, still no difference: I need to make a correction Bolus.

Other people are not as lucky-- and many people get such bad results that they send it back. YMMV! And you must absolutely NEVER let the Sensor get wet, it'll show crazy readings (200, 300 points too high) until it dries out. Many people have this "wetness" problem just from sweating.
- - - - -
So, although the FDA doesn't allow it, I actually use it as my sole meter. I've just got spare One-Touch Ultra machines lying around as back up. When a buzzer goes off at night, I never stop to "check it": I just treat according to what the Dexcom says, and then I go back to sleep. :D

But YMMV. BTW, I am buying the Abbott as soon as it becomes available: "waterproof" is a huge advantage; their claim for even higher accuracy is attractive; and their replaceable batteries are a big + financially. ;) Also, if you call it "CGMS" then people will know what you're talking about, I've never seen "CBGT" as a thread title before (not at Insulin Pumpers' mailing list, nor here.)

[Momof4gr8kids]

Rick,

Thanks for the info. It sounds like the CGM is going great for you!
We were considering getting it for our daughter, but have decided to wait, and see where the technoligy goes. I hope all of the companies continue to compete like this. This race for the best product is really fun to watch! Maybe by the time we are ready to get our second pump they will have it to where you only need to confirm if the readings are weird. Who knows.....maybe the smart insulin will be out by then. Good luck with the Abbot, I hope you have even better results with it! Keep us posted when you get it, and please let us know how it goes for you. I may just make DH the guinie pig before trying it on Julia, lol.

Sorry about the title. I couldn't remeber the initials, so I winged it, lol.