When using add-on codes (ie: 49568 for mesh) with the appropriate codes (49560 hernia repair)...does one need to use a modifier (ie: 59 or 51) ?? I thought the whole reason for the code being an "add-on" code was so that it could be billed in addition to the primary code and did NOT need a modifier. According to Medicare (just in 2013 only), we are receiving denials stating that the add-on code needs a modifier because the CCI edits are showing it, and even after speaking with a supervisor, I was informed that if we didn't apply a modifier to the add-on code, it would definitely be denied as per they CCI edit checks. This has NEVER happened before 2013. Anyone have any insight on this??