Why would real accuracy be difficult to determine? Clinicians get to test these on their patient populations and validate against other high accuracy methods (

Why would real accuracy be difficult to determine? Clinicians get to test these on their patient populations and validate against other high accuracy methods (point-in-time serum draws). For instance, Dr. Peter Attia says he gets a useful fraction of his clinic to use CGMs (as well as personal use), and over years sees a strong signal. There are many other Drs that have gone on record.