i am new to cgm and have only had one for a little over a month, however, i have a number of problems and now realize that when your monitor tells you a high or low you never trust that reading until you confirm with your other bgm. the first time it happened by blood sugar was low at 37 and my cgm told me it was 157. later i corrected the machine, however it kind of defeats the purpose i bought it. i was having hypoglycemic unawarness and for the first time in 33 years passed out due to low blood sugar. i pruchased the new machine to avoid this happening ever again and now find that this is an inexact science. the machine can not be trusted to give you a warning,if it is so far off in the reading.i now give the machine more than 2 bg readings that it requests during the day,especially if my readings have been high or low during the day and have found that this better corrects a reading of over 100 points difference.
does anyone know why this occurs? the manufacturer referred the problem as drifting.
I’ve been using my cgm for several months now and while it is rare, you will occasionally see a 100 point difference! The key to avoid those is to start new sensor while your BG is stable, and keep it stable during the calibration. I have the dexcom and it takes 2 hours to start a new sensor, during which time i try to make sure I am not in middle of bolus or meal effects. It means waiting to eat sometimes, but it’s worth it to me to prevent the wild shifts and errors. And sometimes, it’s just a bad sensor lol, i’ve been fortunate to only have that once or twice. If you call the company and tell them they are usually pretty nice to replace it free of charge, etc. I’ve slept through low alarms sometimes, but overall it does provide a real sense of relief to know what my bg trends are doing. The longer you use it, the better you get at using it…
I agree with bobnominous. I also only calibrate my dexcom with my bg when I am in range and staying steady. Sometimes that means that I do not enter a bg for over 3 or 4 hours past when the cgm is requesting it.
I’ve also heard others state that less is more when it comes to giving the cgm info. For example, if you correct the cgm EVERY time your finger stick differs, it can cause info overload and further keep the cgm from “synching” with your bg.
Lastly, I always give my cgm 2 to 3 days before I start relying on it for more accurate numbers. Thankfully, I can usually get 2 good weeks out of each sensor.
Good luck! Hope you get the hang of it quickly!
so many people say to calibrate while your BG is 'stable.' Well, my BG is rarely stable. And when I did the one week trial of the Dexcom, the nurse told me it did not matter about stability with the Dex. I paid no attention to my BG when I did the twice a day calibrations. I kept meter and cgm records all week and found that the cgm was within their margin of error 90% of the time for me. It also turned out to be a stressful week with a family illness going on, involving a trip for me. So, even so, it was pretty close most of the time. I never had to change it, of course, since it was a 1 week trial. I am getting a Dex soon.
Mine is sort of like a "babysitter" in that if I'm *very* carb conservative, particularly on day 1, it tends to work much better?
I agree with everyone else who has given advice about when to calibrate. Also, I was having lots of calibration issues, and found that "less is more" as well. The first few days can be sketchy, but then i can usually get 7-10 days out of the sensor before it conks out on me. Also, remember that the Dexcom is going to be about 10 minutes behind your fingerstick reading, because it measures from interstitial fluid, and not actual blood, so if you're dropping quickly, it might say "100" when you're actually much lower. CGMs definitely aren't perfect yet. I find that the greatest benefit it gives me is to know which way my blood sugar is trending. It has definitely caught lows for me that I didn't know were happening. I have it set to alarm when the fall rate is dropping quickly, and sometimes even if it doesn't read as "low" it will still alarm when I'm dropping quickly, so I'll know something is going on, and be able to use my meter to find out what's happening. It can definitely be frustrating, and it's definitely not for everyone. Good luck, I hope we can help shed some light on what's happening and make your CGM issues a little less frustrating.
I made the same mistake by treating without finger sticking the first few days and learned the hard way also. My CDE never mentioned that the numbers may not be completely in sync and I obviously didn't read the material well enough. When I think back, my CDE even questioned my "finger stick technique" because when I used the loaner it showed a significant difference with a couple of readings.
I too was disappointed when I found out that I was still going to be finger sticking so often. I thought I wouldn't need to do that anymore. But I've come to love my dex and feel lost when it's doing it's 2 hour setup thing.
Thanks to the veterans on this site, I have learned many things that have helped me feel secure with my dex again.
(1) Follow the tips on calibrating that others have given you here.
(2) Set the alarms for when the fall rate is dropping. That way, even if your dex says your 150, if it's dropping and alarms you, you can finger stick to see what it is.
(3) Listen to your body if you feel anything that doesn't feel right even if it's not a typical symptom of low. I've become hypo unaware except for kind of a scalp tingling or fuzzy head feeling sometimes. I woke up in the night feeling this, checked my dex and it said steady at 102 - I decided to finger stick and it was 72.
(4) If you're experiencing severe lows or frequent lows, you may want to set your low alert at a higher alert setting especially at night - maybe even at 100 or 120. If you do this, you will have more false alarms but you will become more comfortable as you use it longer. This tip is suggested in the Pumping Insulin book by John Walsh (which was suggested by the veterans on this site).
(5) Watch the trend arrows. Those are really the most important piece of information, in combination with your finger sticks.