While and are of course more semantically correct, there seem definite legitimate reasons to use the and tags for customer-written content. Explains the difference between 'rem' and 'em' units in css for font sizing and layout. E/m coding standards and guidelines are based on the current procedural terminology codes and used to document the type and severity of patient conditions.

Check cms documentation guidelines, time-based coding, and get on the fast track to e/m level accuracy.