An NPI is a unique 10-digit number used to identify health care providers. All health care providers who are HIPAA-covered entities, whether individuals or organizations, must obtain an NPI.
Once assigned, an NPI remains the same, even if the provider has a change of name, address, or other information. NPIs do not carry information about a provider, like geographic location or specialty.
An NPI must be used in all HIPAA standard transactions.
CMS has developed the National Plan and Provider Enumeration System (NPPES) to assign these unique identifiers.