Results are considered new until any user in your practice views the results report. On the Practice Results page, there is an option to Show All results (including those that have been viewed) or to Show New results only (which hides those that have already been viewed). When viewing a results report, you can mark the report as viewed by clicking the Mark As Reviewed button at the bottom, and you can also add annotations to the report.
After marking the report as reviewed, a Reviewed By message appears in the result details that includes the name of the user who marked the report as reviewed and the date and time it was reviewed. (Results can only be marked as reviewed once, and it cannot be undone.)