HCPCS modifiers X{EPSU}

April 14, 2015 CMS held an Open Door Forum. The chief medical officer of Program Integrity said this:
CMS released CR8864 describing four new modifiers, a subset of modifier 59 last fall. MedLearn Matters articles followed. CMS stated that further information would be forthcoming in the months and years ahead, and that groups could continue to use modifier 59. As of this date, CMS is still developing these instructions and has no stated time frame as to when they will release them.

CMS’s advice in this call is that there is no reason for not continuing to use modifier 59, and no advantage to using the new modifiers. It continues to be acceptable to use modifier 59.

My advice based on this CMS Open Door Forum: ignore the new -X {EPSU} modifiers until we have specific CMS instructions.