Initial CMS-855A applications and ambulatory surgical centers and portable X-ray suppliers submitting an initial form CMS-855B can be submitted up to 180 days prior to the effective date listed on an application. All other applications can be submitted up to 60 days prior to the effective date you provide on your enrollment form.

References:

• CMS IOM Pub. 100-08, Chapter 10, section 10.4.1.4.2 A