The Medicare physician fee schedule status indicators for bilateral services should be used to determine if the procedure is allowed to be performed bilaterally.
This provides definitions of the national policy indicators for each procedure code (and modifier, where applicable) on the Medicare physician fee schedule database (MPFSDB).
To access a file containing the quarterly additions and deletions to the list of ZIP codes requiring a plus four extension, refer to this link to the CMS website.
This document discusses the conditions and requirements of the Item fields within the revised CMS-1500 (02/12) paper claim form and the electronic equivalent elements.