A National Provider Identifier (NPI) is a unique 10-digit identification number issued by the Centers for Medicare & Medicaid Services (CMS) to health care providers in the United States. It is used to identify providers in all health care settings, including hospitals, clinics, and private practices.
Sole providers are health care providers who are not employed by a group practice or other organization. They are self-employed and typically own their own practice. In order to bill Medicare and Medicaid, sole providers must have an NPI.