CMS 855O--Medicare Enrollment Application for Eligible Ordering and Referring Physicians and Non-physician Practitioners
http://www.cms.gov/Medicare/CMS-Forms/CMS-Forms/Downloads/cms855o.pdf
Form 855O is completed by the following Physicians and Non-physician Practitioners:
--	 Employed by the Department of Veterans
--	 Employed by Federally Qualified Health Centers Affairs (DVA) (FQHC), Rural Health Clinics (RHC) or Critical Access Hospitals (CAH)
--	 Employed by the Public Health Service (PHS)
--	 Licensed and Non-licensed Interns, Residents and Fellows in an approved medical residency program
--	 Employed by the Department of Defense (DOD)/Tricare
--	 Dentists, including oral surgeons
--	 Employed by the Indian Health Service (IHS) or a Tribal Organization
--	 Pediatricians