I have been wearing the Libre (or Libre2) now for at least 7 years and what I have found it - the readings on a day to day, hour to hour or minute to minute fluctuate quite a bit compared to a stick test within the 15 minute window around the sensor reading

But at the end of 90 days my Libre has "always" correctly calculated my A1C within 0.1% of a Lab Draw A1C test

CGM's are Not Stick Tests and we can't look at them the same way. Our blood sugar changes by the second and can rise or drop many points at the snap of a finger

Plus it's measuring the sugar that is floating in fluid around the cells not the sugar in our capillary blood that the stick test measures (which is different from the plasma that is tested in a lab A1C, FBS or Random)

Bottom line is they just aren't measuring the same thing. And the CGM does the equivalent of 1440 stick tests "A Day" and when it does it's voodoo for 90 days it's giving effectively the same result as a Lab A1C Test

So I have stopped caring if my CGM is giving me a "close to my stick test reading" unless it's clear the Sensor has gone flooey (and I haven't had one fail in over 2 years now - they are getting the bugs out)

But just for the sake of giving my arm a break from stabbing it in the same place with each sensor, I do alternate arms - and again, over the past number of years that has made zero difference to the comparative accuracy between the 90 days of Sensor vs Lab

After 7-8 years of constant cgm use I have not noticed any difference between the readings of arms..I change arms whenever the sensor expires.

Always found testing right or left with finger stick was equally as different.
I have only been using the cgm a few months. And I think the sensors differ more than each arm.

There might be a slight difference but not by much, maybe 0.1 to 0.5 for me. I know my Fbs is never accurate so I finger stick most morning if I feel the sensor is way off. The sensor measures interstitial fluids, so not blood so yes you might get a different reading from blood finger stick for sure. If my Libre is on my right, which is the side I sleep on, then the morning numbers are never accurate, but after 1 or 2 hrs it catches up, I believe it is similar to when we did BP on patients wether done on the side they are lying on or the oposite, because of compression (as in lying on the side of the sensor it will initially give you results much different then lets say 1 or 2 hrs later. I never sleep on my left arm (torn shoulder never repaired since 2007), so yeah sometimes it seems it is more accurate in the morning, but then again I am not lying on that side so no comprassion factor. So this can come into play also which side you sleep on. But as Graham pointed out the 90 day average is usually right on with lab tests, the Libre can be behind anywhere from 5 to 30 min with your finger blood sample, Abbott Canada told me to recheck sugar level around 20 to 30 min after finger stick and you should get same results. They have improved a lot as in the past many for me were not accurate. Don't forget when you are sleeping everything slows down, Heart rate, blood pressure, so once you get up and move around your heart starts pumping stronger and faster so this could also come into play for morning sugar levels.

If you doubt the numbers you are getting, then do finger stick, especially in the morning with that get up and go routine, the fluids between the tissues change faster also as our system speeds up. The new Libre 2 system does work better then the 1 used too for sure. Also I rarely ever get any Libre coming off, even when accidently hitting a door frame from balance issues. The only isses I have had the last few months was twice when i applied the Libre 2, blood came pouring out from the middle of the disc, this mean you need to take it off and apply pressure to stop the bleeding and use the other arm or a different site, but that has nothing to do with the sensor itself, but more because your blood vessels may be close to the surface and the needle pokes through it, when this happens I call Abbott and they will replace it, but you need to keep the boxes when you apply them with all the mechanisms in the box, as when this happens or a Libre does not work well, they might ask your to return everything so they can check the springs and other componants to see if there was a defect. They are very good and have excellent customer service, I have never had to pay for any replacements ever.