HIPAA applies to any entity that falls within three categories.
Health Care Providers
Doctors
Clinics
Psychologists
Dentists
Chiropractors
Nursing Homes
Pharmacies

Health Plans.
Health insurance companies
HMOs
Company health plans
Government programs such as Medicare, Medicaid, and the military and veterans health care programs

Health Care Clearinghouses
Companies that function as intermediaries who forward claims information from healthcare providers to insurance payers.

An entity that is one or more of these types of entities is referred to as a “covered entity” in the Administrative Simplification regulations. These are entities that transmit any information in an electronic form in connection with a transaction for medical and health information as defined by HIPAA.