CMS 855A--Medicare Enrollment Application for Institutional Providers http://www.cms.gov/Medicare/CMS-Forms/CMS-Forms/Downloads/cms855a.pdf Form 855A is completed by the following Institutional Providers: -- Community Mental Health Center -- Hospital -- Comprehensive Outpatient Rehabilitation Facility -- Indian Health Services Facility -- Critical Access Hospital -- Organ Procurement Organization -- End-Stage Renal Disease Facility -- Outpatient Physical Therapy/Occupational Therapy /Speech Pathology Services -- Federally Qualified Health Center -- Religious Non-Medical Health Care Institution -- Histocompatibility Laboratory -- Rural Health Clinic -- Home Health Agency -- Skilled Nursing Facility