The HIPAA privacy rule only applies to a select group of health-related organizations including health plans, health care clearinghouses, and certain health care providers.
Health plans include insurance companies, health maintenance organizations (HMOs), employer sponsored health plans, and government claims programs (Medicare, Medicaid, etc).
Health care providers including doctors, clinics, psychologists, dentists, chiropractors, nurisng homes, and pharmacies that submit claims electronically.