Is less more when it comes to calibration?

I have read several posts in various forums that suggest that less calibrations is better but logic in my mind would suggest that if you calibrate whenever you are in range of your Norms the better.


If you are suddenly High or Low , the delay to the trend would be telling the sensor a false value as it takes the last 4 calibrations as part of its math.

The Question :
Should you calibrate whenever you take BG reading and it is near your Norm Range ?

Would appreciate experiences and logic from experienced users in that I am new to the CGM.


It’s hard to say, but it probably depends on the algorithm and the quality of the calibrations. I’m mostly flat at wake-up, late afternoon/before dinner, and at bed time so I calibrate at those 3 times unless I’m off. Before lunch or after exercise are good back-ups, but I don’t typically use them for fear of introducing unnecessary error because I’m usually moving a little bit more at those times. If you tend to be really stable at other times, then I don’t see the harm but it would depend on how the algorithm handles them and it’s hard to know how they’re weighted and if they get ignored.

As part of a recent study I was also told by the study doc not to calibrate the navigator unless it asked for one because doing so would be a forced calibration and erase previous calibrations. (I’m not sure if it applies to all navigators or just the study device.) I’m not aware of a similar quirk to MM or dex, but I have suspected in the past that my MM has ignored calibrations.

For the MM unit you will be far better off if you only calibrate when your BG is stable and in the normal range. And, as long as your BG is tracking well with your CGM there is no value in calibrating more often that is needed; every 12 hours.

If you are using a MM 522/722 pump, CGM calibration is difficult with unstable BGs. With the 523/723 you can calibrate all you want, except when is displays a “Out of Calibration” message. Then you may need to shut off and unlink the CGM and pump, they start the calibration again by restarting the sensor and relinking the CGM transmitter and keeping you BGs stable for the first few hours.

The difference between the X22 and X23 MM pump is like night and day. The product is completely different and worth every penny for the upgrade. It is still not magic though, only another technology that makes T1D management easier and more effective.

I was told by the MM person who trained me for a one week trial to only calibrate twice a day. She said NOT to calibrate more often. She also said it did not matter whether my BG was “stable” or not, that most of us are going up or down most of the time. My meter and sensor were within 15-20 points 90% of the time. Take your pick of the answers!! Or ask your MM rep.

Can you be specific about the product you are referring to Neil. Which pump were you using when getting trained by MM. The X22 and the X23 are very different and are not calibrated the same way.

Sorry. It is on my profile but I use a Paradigm 715. Didn’t know about the variation in MM pumps. Yep, some of us still have the oldies.
I still think you should ask your MM rep about questions like this. It is better to get some info from the pump maker staff than from users.

No matter which CGM you’re using, all the CGM makers recommend calibration when steady, when in the normal range, when not expecting it to go either up or down soon…

I was also told nto calibrate no more than 3-4 times per day. I tend to overcalibrate anytime the BG and SG are close and I don’t know if this affects my readings at all.