Calibration questions, general ones and Libre specific ones

I am using a Libre with a Miaomiao receiver and xDrip. In xDrip, I have the libreOOPalgorithm enabled, which sends the Libre readings through Abbott’s official algorithm and computes BG data that is shown in xDrip. In other words, this makes sure that the xDrip BG readings and the Reader’s BG values match.

One reason I do this is that apparently the sensor does some internal calibrations sometimes. When I was using xDrip without libreOOPalgorithm, I saw sometimes weird BG drifts of over 30 mg/dL over half an hour, and these drifts were not detectable with a BG meter … or with the Libre reader itself. This tells me that something inside the sensor is readjusting, and that the reader knows about this, but xDrip doesn’t (because not all values from the NFC blocks have been reverse engineered).

But I’d like to give xDrip and calibrations a chance again, because trusting the Abbott algorithm always left me with a sour taste. To that end, I’d like to know if anybody else is also using the Libre like this (with a transmitter, xDrip, and calibrations).

The recommendations are to calibrate at multiple BG levels. But this won’t be possible unless I either provoke a higher BG by eating some carbs without correction & provoke a low by injecting without eating carbs. Not a good plan. And calibrating post-meal hardly ever works, because the BG just isn’t stable post-meal, which is why I disagree with the points listed here. Calibrating with unstable values introduces the error that comes from the interstitial lag.

So how do you do this?

I use the Blucon with the Spike app and you have to calibrate it. One thing you are forgetting I think is that trusting any reading from a CGM comes with a risk and that’s not even taking into account that meters are often wrong (even the best ones). Since I don’t use xdrip I can’t answer your more involved calibration questions but with Spike as long as your BG is stable calibrating it is simple and works like it’s supposed to.

Since the Libre is wonky sometimes I generally trust the readings on the Spike app more than the reader. I usually only calibrate once per day when I wake up in the morning (which is when my BG’s are the most stable). If my reading are really far off at a later time during the day but the app thinks I am stable then I will calibrate it but this only happens once or twice a week.

However if my actual BG is over 250 or so then the reader and the app will be wrong and calibrating it then will just mess up the readings when my BG comes back down so I resist doing it.