We never took a test for the flu before. They had access to a name, a sample, and a phone number for all who were tested. Whether they kept the "data" is questionable.
I had a tinfoil hat moment thinking about this. It is a fairly easy way to get a catalog of your subjects and their qualities. Once it is digitized, you can query for those whom have the traits you want to keep, who to kill, who are to become slaves.