Ok, I received my first CGM and

I love it! Would someone be kind enough to help me figure out a problem? I know it has probably been talked about before, but since I am not at my best right now, I don’t want to search for the answers.

The first few hours were very good. I have had it on about 16 hrs now and the only time I have been out of range was once at night and then the machine went crazy.

The first low at midnight woke me with a 60 reading. That was not a mistake, but then the next 3 were of course, while the tiny bit of sugar finally registered in my system. I will be sure to put a glucose tablet by my bed instead of dried fruit. I did a finger check and all was well. Couldn’t sleep so checked the monitor and I was at 90 and holding steady. Then another low signal. Sometime in here I changed the alert to 60 down from 70. About 1:00 I had a low alarm with a 55 while my finger stick said 88. Later an urgent alarm of 45 while fingerstick read over 100. I finally turned off the alarms. I completely trust my regular glucose monitor. Before this happened, the two monitors were fairly close.

Will this just work it’s way back to working correctly or should I be doing something to try to fix this problem. I calibrated it and it seems to be working ok.

Thanks for any help.


Your on a G6? What time did you start the sensor? What time where you seeing error? Did you calibrate the device? Could have been a compression low, but it depends.

Oh sorry, G5. It started reading at 4:00 pm, yes, calibrated it. First false reading about 1:00am. Finally turned the alarms off at 2:00am

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Was your blood sugar stable when you first calibrated it? Like, you hadn’t eaten in the last couple of hours, or given correction insulin within the last four hours? You might not remember, but thats important for proper calibration. You want to calibrate when you see a --> arrow indicating stable behavior. Rapid changes in BG will make for a crappy calibration because of the 15 minute lag between actual BG value and sensor reading.

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I don’t think it was a compression low since it is on my stomach and I sleep carefully on my side because of sore ribs. Could be though I suppose.

Its probably just sensor error. But, I wanted to mention that upfront because someone will bring it up. You might want to eat more than one tablet to keep it from waking you up. Like, try to bump it up to 120, to eliminate overnight alarms. Its a pain to get woken up all night.

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I always wear the sensors for a DAY before putting them into service. ie, I “soak” them so that the first day that I install the active transmitter, the first day data is very good. It is very common for day one to be a disaster, data-wise. I install an old transmitter onto the new sensor to keep the filament in place. The next day when I’m ready to place it “on line” i swap the active transmitter from the previous sensor (which I’m still wearing at the moment) to the new sensor. Just stick your fingernail under one side, then the other, to release the transmitters. Once I get the new sensor up and running, I then remove the previous sensor.


Good questions. My average of the two finger sticks was 109. I hadn’t eaten for about 3 hrs and I used no corrective insulin. Don’t think I noticed the arrow that time, although I have sure been focused on it since then.

This will be a lot of fun, if I can stop getting false lows. Broken sleep isn’t welcome. Wish I was one of those people who fall asleep easily.

See my comment above! If you have only one transmitter, you won’t be able to follow my method exactly. You will then need to secure the filament as best as you can, or it can come out, prior to installing a transmitter. ie, if you were to raise up the contact pad, you would find out to your dismay, that a very gentle tug would yank the filament right out of your body, thereby destroying that sensor.

BTW, it is pretty common for folks to “soak” the G5’s.

FYI: Don’t throw out your old transmitters, as they are what you use to secure a “soaking” sensor.


Welcome to the CGM club!!! The first month will be the OMG month where you learn all sorts of stuff that you knew you knew before and find out you now really know stuff much better. You may want to leave all alarms off for the first few weeks until you get to know your CGM and its quirks and it gets to know you.

If you go to bed with a BG under 68, the G5 will sometimes tank for no reason at all. DO NOT CALIBRATE, If it says you are 48 and your finger stick says 78, leave it alone and it will fix itself by morning. The more you calibrate the G5, the worse it gets. I only calibrate each day at 8AM and 8PM.

You will learn a lot in month 1 and it really won’t affect your A1C. In month 2, you will most likely inch your A1C (GMI on clarity report) up a bit due to curiosity. You will start wondering based on what you learned in Month 1 how certain foods react with your body and you will want to validate what you thought you always knew based on finger sticks. You most likely will push the envelope to see how you can expand your food groups, some of which will be detrimental and cause your A1C to go up a little.

Month 3 you will start to micro manage your BG starting by determining the absolute best time to pre-bolus for meals and how much to pre-bolus. From there you will just keep getting better at it.

In the meantime, enjoy the ride - you will love it and learn to deal with expanded possibilities for food and exercise as well as beating the Dexcom company occasional frustrations.


For me 1 glucose tablet would have been plenty. My half of a dried fig would have been enough, if it had digested fast enough. The only time I was woken up correctly last night was the first time. I tend to rise in the early morning and if I eat too much for a low, I will wake up over 150 at 6:00am and I hate that.

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Thanks Dave, I have some of that tape you mentioned in an earlier post arriving from Amazon tomorrow. Since I am not at all active right now, I am hoping that everything stays in place. If it doesn’t I will be letting Dexcom know.

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I guess u mean the overtapes, which are free for the asking from Dexcom tech support.

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Sensor on your belly? False “compression lows” from rolling over onto the sensor happen to me in bed. On a graph these look like a RAPID departure from an otherwise flat bg. Some sites on my belly, seem to have been more sensitive to this than other nearby sites.

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You will probably want to fine tune with candies rather than glucose tablets. I use Swedish Fish, others use skittles. For me, each swedish fish will raise my BG 10 points so if I drop to 68 and want to go to 98, I just eat 3 Swedish Fish and done. Just remember that although we are all a little different, it takes about 15 minutes for the candy to take effect (you will soon know for you how long down to 1 minute) and then 1 hour to reach peak. Find yourself a candy you like and can use to fine tune as that will keep you away from pesky night alarms once you have those properly set.

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Thanks CJ. I have only calibrated at the start and then 12 hrs later. I thought I had started using the monitor at 4:00pm but it was at 6:00 pm. So 6:00 pm and 6:00 am is when I calibrated. So far my results are exactly what I would have predicted. I can’t see myself changing my diet at all because it is quite varied. To vary it more I would have to add fat and I am not going to do that unless I find that my anemia is connected to my diet.

I am looking forward to keeping all of my readings between 65 and 150. Of course once I can exercise again, I will have to refigure everything again.

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It is probably advantageous that you can’t exercise right now. Exercise depending on stress, temperature, humidity, exertion, etc. will all affect your CGM values so best nail down the food first and then work in the exercise one step at a time.

Yes, get into a groove to always calibrate at the same 12 hour times. If you are early or forget once or are not exactly at 12 hours, don’t sweat it. The CGM runs fine and if you miss just get back on schedule the next day.


The alarms can be annoying at first, but really it’s usually the first 12-24 hours they do the false low thing. Not all do that for me, I just get one off and on that do, of course it usually never does on a restarted sensor. I forgot you got a G5, I believe it’s easy to restart those? If it is a problem you might try the soaking method.

BTW, I’m not sure about the G5, but if you don’t press the button for the CGM on your phone or reader it will keep setting off the alert while you are even just 1 point under. Plus in the settings for the G6 you can tell it to repeat and at what time you want it to repeat a warning if you are still low or high. So for a high I have it repeated for an hour later as by then I should be able to tell if I need more insulin or not. A low at 15 minutes!

But I have a G6 and I am not sure if a G5 is the same? Someone here should know!

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Just a quick suggestion from an alarm standpoint. Yes, it takes awhile for the system to catch up with the rising blood sugar and those repeat alarms are what make many people give up on CGMS. Alarm fatigue!
So I learned to adjust the snooze alarm. I have my repeat warning of lows set at 45 minutes. So after the first alarm and treatment, if it is still low I will get a repeat at 45 minutes not every 15. The same for the high repeat. I have my repeat at 120 minutes because sometimes it can take a very long time for those stubborn highs to come down. And if after 2 hours it hasn’t come down, I can do another correction or use Afreeza or change the site-whatever I need.
Alarm fatigue is very real and I always hate to hear how people give up on the technology because of alarms.
So very happy you are up and running! Hope you get as much out of it as I have over the years!

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@Sally7 The only problem with a low warning being 45 minutes is catching it in time if you keep falling or the hypo treatment isn’t enough? After snorkeling one time in rougher waters I dropped unexpectedly about 4 hours later. I usually reduce basal and eat and that’s been fine. But this time I crashed and pretty fast, ate my hypo candy to bring it up and then as soon as I saw my arrow and numbers go up, I promptly dismissed it as past. About 10-20 minutes later I crashed even worse, but this time because of no warning I ended up sweating, shaking etc and ended feeling like junk because of it. I never went above my low warning number so it didn’t signal a low alarm again. And I already felt a little off because of the first crash so I didn’t notice another crash coming until it was already low. I promptly changed the repeat to 15 minutes.

But yea, I remember at the beginning setting all the alarms and within a day turning most of them off lol…very annoying especially when you aren’t used to it. As time progressed I figured out which I wanted and at what levels worked best for me.