Level I, Provider Grouping
A major grouping of service(s) or occupation(s) of health care providers. For example: Allopathic & Osteopathic Physicians, Dental Providers, Hospitals, etc.

Level II, Classification
A more specific service or occupation related to the Provider Grouping. For example, the Classification for Allopathic & Osteopathic Physicians is based upon the General Specialty Certificates as issued by the appropriate national boards. The following boards will however, have their general certificates appear as Level III areas of specialization strictly due to display limitations of the code set for Boards that have multiple general certificates: Medical Genetics, Preventive Medicine, Psychiatry & Neurology, Radiology, Surgery, Otolaryngology, Pathology.

Level III, Area of Specialization
A more specialized area of the Classification in which a provider chooses to practice or make services available. For example, the Area of Specialization for provider type Allopathic & Osteopathic Physicians is based upon the Subspecialty Certificates as issued by the appropriate national boards.

The Health Care Provider Taxonomy code set Levels are organized to allow for drilling down to the provider's most specific level of specialization. The ten digit codes for each provider category are unique and contain no embedded logic. The codes and categories are to be used exactly as they are assigned in the Taxonomy list. At no time should codes be separated to form new codes, parsed apart, or edited on any one position within the code. See "How do I request a change?" if you identify a need for a provider category.