[Diabetes-Talk] which meter is right

[Amber Wallenstein]

I got my libre up and running with my phone and that is nifty.  
But why am I getting different readings on my blood sugar with different machines? With my prodigy I get a reading that’s about 20 points lower than the libre. Which one is right and why would I be getting different readings when doing the readings at exactly the same time?
Thanks.
Amber