My son just started on the newest CGM this week. Somewhere along the way, I interpreted the CGM as a monitor I could count on most the time (in place of using a meter all day long.) We do calibrate the CGM twice per day (the readings have been spot on with our meter) and of course, if anything seemed "off" we would double check with the meter. However, I was shocked today our dr's office told us he has to use his meter just as much as he was before (8 times per day!) So what really is the point of wearing this thing??? It is working fine, and we haven't had a reading yet that wasn't within 10 points of the meter. So I guess, if he is feeling fine, why can't we count on the CGM when the new model has 87% accuracy. I feel like it is so redundant to check with a meter every few hours when he's wearing it. Also, he HATES wearing it, and the only way I have been able to bribe him to wear it (he's 11) is telling him he doesn't need to check himself with the meter but just here and there! But I guess I dreamed that up on my own. Ugghhhhh very frustrated to learn this or is my doctor's office exaggerating to cover their behinds in case something wasn't accurate?
You didn't dream it up on your own and I think your son's doctor's office is just covering their butts. But they may also be more used to the old CGM's which were not particularly accurate. It will take a while before the doctor's office can see the correlation between the twice daily calibration and the actual readings you get from the dexcom itself. I now use my meter twice a day to calibrate it and if it says I am low otherwise I rely on the CGM all the time. If you haven't had a reading outside of 10 points from your meter I would agree it is redundant to continually check with the meter and do fingersticks to prove it is correct.
I'm sorry he hates wearing it, I have found that the sensor placed on my arm is totally comfortable and I don't notice it at all. While this is not where the dexcom was "approved" for use by the FDA it certainly beats having it stuck on my stomach.
There is a really good Dexcom users forum here where you can post questions specifically about the G4 or CGM's in general.
All I can give you is my personal experience and I have been uniformly impressed with the G4 and how accurate it is. I'll let my endo's office catch up with the newer technology when they can, but since the G4 was only very recently approved by the FDA I know there are many doctors who are not familiar with it.
i'm kinda starting to hate wearing this Dex G4 too, especially on my stomach (very little real estate) and with a pump starting tomorrow. ugh. I put it on my arm yesterday, although I have very little fat....it doesn't bother me at all on my arm but it did take a full day of messed by CGM numbers to get it to work better.
So actually, the official role of the CGMs is as a monitor and almost all medical professionals will tell you to only make treatment decisions based on meter readings. I think some CGM users may feel comfortable doing meal boluses based on CGMs, but it is still a risk. And taking corrections based on a CGM reading is even more problematic. Still, the CGM should let you avoid most postprandial meter readings and if you time things, you can make the preprandial readings count for calibration. I don't think that has to add up to 8.
I got the 7+ about 2 years ago and the g4 this fall. Since going on the cgm I test more often then before (usually about 8 - 12 times per day). I know that g4 is very accurate and most of my sensors are within 10 points of my actual blood sugar. But it does not change the fact that a cgm does NOT test blood. It's interstitial fluid. And while it gives a great trend, I am not comfortable relying solely on it when giving myself insulin. Anytime I bolus, I test first. No matter what. Pain in the neck? yep. But the "what if it's wrong this time?" scenarios are too great IMHO. I think your doctor gave good advice and don't think it's a CYA kind of line.
As to your son not liking it, have you tried different locations or even taking a break on weekends or one week a month? Sometimes that's what I need to feel less cyborg-like :)
me too, sometimes I test more because CGM is saying dropping, I'm low, low or high high and I'm not if I test on my meter. NEVER do a correction or take insulin while using your CGM for a guide. Many times the CGM is spot on if I'm steady but it can also say I'm dropping to the 40's when I'm in the 80s. It serves the purpose of providing data and trends, especially middle of the night and shows spikes etc after meals.
i've done some over correcting too many times with the CGM because it's given me low, low, low's when my meter hasn't, it makes me kinda freak out like 'am i really dropping this low'. But, when I change out my sensor and it's recalabrating and now working 'yet'..i feel like I'm kind of becoming 'dependent' on it, feel reassuring in a weird way too.
I agree with Kate and Sam unfortunately. I have a Minimed CGM (not the greatest, but better than nothing..) and it is 4:00 now and I have already tested 6 times. I also find that mine is accurate about 80% of the time. But I never count on it to bolus or correct---ever. I check, on GOOD DAY, seven times per day. Problem days? Don't even go there!
The MM CGM is about 20 minutes behind my actual reading. So if it alarms me for a high or low glucose reading, it is probably worse.
Tracey, I also hate my CGM and I am a great deal older than your son. However, it keeps me out of trouble---real lows and highs--and helps me organize my readings to more of a flatline. If I had been able to use one 50 years ago....
It is tough with a child. I get it, as it was me. He will still need to test a lot.
I have the Medtronic CGM and test a lot, maybe 8-12x / day, because I like having pretty tightly controlled BG and like being active. I also like trying to kick diabetes' ass as much as possible and think that helps. Perhaps something along those lines might make it more marketable to an 11 year old than "the doctor says so"
I test on average 10 x per day, even while wearing the G4 24 x 7.
(Before the CGM, I tested 12-15 x per day).
I think it is somewhat dangerous to rely solely on the CGM when dosing insulin. I have occasionally found the G4 significantly off from the BG meter, most scarily on the low side. I have had instances where the CGM read 80, yet I was really in the 60's. 80 is a good number.... the 60's start to get close to danger. If I had not tested with the BG meter I would have been blissfully ignorant until something bad happened. THe G4 is certainly better than the 7+, but it is still not good enough, in both the opinion of the FDA and the manufacturer, to be a substitute for a BG meter.
Perhaps the G5 version will make it to that level of accuracy and precision.
Why should the G5 be more accurate? These devices are accurate for the environment they are operating in. The glucose level in the interstitional fluid is always different from the level in the capillary blood. The problem is that the difference between capillary and interstitional fluis will be equalized by diffusion processes. This will always take its time. Most likely 15 to 20 minutes depending on the blood circulation in that area. Even the blood in the finger capillary is some minutes behind.
Imagine you are flying an airplane in the simulator. In this simulator you will see the landscape as it was 15 minutes ago. Can you interpolate from that where the plane might be now? Can you land it safely and spot-on with that information at hand? I think it is not possible - even for a pro like you. In my opinion this is why cgms can not be used for dosage decisions. They are fantastic for trends but with rapid changes in blood glucose they will often be too late or too erratic.
I meant the new Dexcom is more accurate at reading interstitial fluid than the older Dexcom model was. I do realize that glucose meters and CGM's are measuring two different environments. What puzzles me is the Food and Drug Administration requires all blood glucose meters to be accurate within a 20 percent margin of error for readings of 75 mg/dl or higher when compared to plasma readings. So neither are 100% accurate. I just find it interesting that our physician want us to rely 100% on our meter, when it has an a margin of error of up to 20%. Our doctor is telling us to rely on the meter reading over the CGM reading, but how do we really know its the meter that is more accurate when meters also have variability. If I check my son's blood sugar using three different meters we have at home, we get three different readings. Sometimes they are very close (i.e. within 5 mg/dcL) but other times they can be 50 points off. So far (we are only in week two) the most variability we have had between the CGM and his meter is 15 points. Yesterday, the most variability we had was 5 points. Since there is a 15-20 minute delay to equalize glucose levels in the interstitial fluid, why is the CGM so spot on to our finger prick each and every time?