US Medicare Provider and Supplier Enrollment (42 CFR Part 424 Subpart P) 424.520-522: Know your effective date of billing privileges: survey or accreditation date for certified providers, the later of filing and first service for physicians, practitioners, ambulance, OTP, Part B hospital departments, labs, therapists and the other listed types, and the receipt date for CMS-855O

The effective date of billing privileges for providers and suppliers requiring State survey, certification or accreditation is set by 489.13; for independent diagnostic testing facilities by 410.33(i); for DMEPOS suppliers by 424.57(b) and the statute. For physicians, non-physician practitioners and their organisations, ambulance suppliers, opioid treatment programs, Part B hospital departments, CLIA laboratories, intensive cardiac rehabilitation facilities, mammography centers, mass immunizers and pharmacies, radiation therapy centers, home infusion therapy suppliers and physical, occupational and speech therapists, the effective date is the later of the filing date of an application subsequently approved and the date services began at the new practice location; a reassignment of benefits takes the same effective date; and a Form CMS-855O enrollment solely to order, certify, refer or prescribe is effective on the contractor's receipt date if all requirements are met.