When they say not to calibrate the g6 unless it is 20% off what is the measurement in millimoles?
This might help you …
Since 20% is a relative amount, it would vary by the number itself, rather than absolutely. Examples, taking 20% as variance:
5 mmol/L = 1.0, 90 mg/dl = 18.0
6 mmol/L = 1.2, 106 mg/dl = 21.2
7 mmol/L = 1.4, 126 mg/dl = 25.2
8 mmol/L = 1.6, 145 mg/dl = 29.0
If you are converting between the two measurement systems, and this will be a long-term concern, you might need to create a table, or use some simple calculation.
20% will apply to whatever unit you are measurement unit you are using.
Here is dexcom documentation for 20/20 rule. 20 points under 80
20% over 80
(or mmol equivalent).
Most of the time you’ll probably using >80, so 20% applies.
From dexcom website.
If you’d like, you can calculate the 20 rule on your own. The Dexcom G6 reading must be within:
- 20% of the meter value when the meter value is 80 mg/dL or higher
- 20 mg/dL of the meter value when the meter value is under 80 mg/dL
Please note: the information listed here is applicable to Dexcom CGM users within the US only.
I honestly don’t care what numbers they say to calibrate at or how often. I want mine to be within 5 points ( .3 mmol) so I calibrate when it first starts or restarts, Then I try to wait a few hours to calibrate again. By the next morning I then fine tune it to be within 5 points.
That’s an amazing level of accuracy, Marie. I’m glad you mention that you are able to achieve this, otherwise I would never think that was possible. I think that even trying to do this would break the algorithm for me. Its so interesting. But, I had better accuracy on G4. I would not have thought changing models would make so much of a difference, either.
Personally I think Dexcom wants you to accept that 20% off is okay so you don’t want to try to replace a sensor that keeps being off. But I always calibrate at around 100. It will be off more when you at at " higher " numbers but I don’t care about that for my purposes.
I’ve calibrated mine when it’s been within 5 points, 7 points etc because I want mine to be within 5 points and I want it within 5 points over what I’m actually at, my preference is for it not to be under. Some take more work than others. But one thing I always do is consistently check it at about the same numbers and calibrate it around those numbers. That is around 100, if I check it at 150, I know it can be off by more. I am not afraid to screw it up as I can always restart them. But I haven’t had to once I learned to do the exact number 2 times, one right after the other and it takes that second number.
Be forewarned that if you calibrate a new sensor or a restarted sensor with my 2 numbers in a row, it doesn’t stop the adjustments of a new algorithm so you will still end up with a new sensor that in a couple of hours wants to raise your numbers and a restarted sensor that might lower your numbers as it thinks it needs to adjust.
So that suggests even if you calibrate it when its under 20% it is still ok! Thats good to know because when it gets over 10%, it really makes a difference in the values.
Also I’ve done a few calibrations. In the scenario where my sensor was higher than my meter, I find it overcompensates after I calibrate… so that it will end up with my sensor reading lower than my meter reading. Do you find yourself lying to the pump and punch in a number very slightly higher (so if i was 5.3 mmol, I would put in 5.4mmol) than your meter reading so that it doesn’t overshoot.
Hey Marie20, can I inquire with you about something that popped up in another post?
Wondering about your sensor placement and if sensor location might possibly be a contributing factor for some of us getting a lot of error.
Do you always put yours in the same place? Do you put it into your abdomen? Or, do you move it around?
@mohe0001 I always put them on my arm. I like the front the best but I rotate them and use the back of the arms too. I just try on the front of the arm to not put it right over a muscle. Plus I always restart as much as possible and I calibrate them as often as needed until I get the numbers I want. And I always calibrate it around 95-105 to make sure I consistently compare it around the same numbers. I expect it to be off more at 140 or 150.
I’m not afraid of messing them up as I can always restart one. But with double calibration that hasn’t been a problem.
Is there a way to tell where the muscle is?
@tedos…I can see my largest arm muscle, maybe not smaller ones, but I meant the larger one at the top of your arm if you crook your elbow with a fist pointed up you should be able to see and feel it?
You can tell where the muscle is by flexing and feeling for the part that is jiggly. Go for that !
When you start a sensor with no code and it asks for calibration, the +/- 20% rule doesn’t apply here does it? Because my sensor seems to be pretty accurate with my meter reading when it asked me for a calibration. If I ignore it, it just keeps asking.