National Provider Identifier
A National Provider Identifier or NPI is a unique 10-digit identification number issued to health care providers in the United States by the Centers for Medicare and Medicaid Services (CMS). The NPI has replaced the unique provider identification number (UPIN) as the required identifier for Medicare services, and is used by other payers, including commercial healthcare insurers. The transition to the NPI was mandated as part of the Administrative Simplifications portion of the Health Insurance Portability and Accountability Act of 1996 (HIPAA), and CMS began issuing NPIs in October 2006.
HIPAA covered entities such as providers completing electronic transactions, healthcare clearinghouses, and large health plans were required by regulation to use only the NPI to identify covered healthcare providers by May 23, 2007. CMS subsequently announced that as of May 23, 2008, CMS will not impose penalties on covered entities that deploy contingency plans to facilitate the compliance of their trading partners (e.g., those healthcare providers who bill them). The posted guidance document can be used by covered entities to design and implement a contingency plan. Details are contained in a CMS document entitled, "Guidance on Compliance with the HIPAA National Provider Identifier (NPI) Rule." Small health plans have one additional year to comply.
All individual HIPAA covered healthcare providers (physicians, physician assistants, midwives, nurse practitioners, nurse anesthetists, dentists, denturists, chiropractors, clinical social workers, physical therapists, athletic trainers etc.) or organizations (hospitals, home health care agencies, nursing homes, residential treatment centers, group practices, laboratories, pharmacies, medical equipment companies, etc.) must obtain an NPI for use in all HIPAA standard transactions, even if a billing agency prepares the transaction. Once assigned, a provider's NPI is permanent and remains with the provider regardless of job or location changes.
Other health industry workers, such as admissions and medical billing personnel, housekeeping staff, and orderlies, who provide support services but not health care, are not required to obtain the NPI.
The NPI must be used in connection with the electronic transactions identified in HIPAA. In addition, the NPI may be used in several other ways:
- by health care providers to identify themselves in health care transactions identified in HIPAA or on related correspondence;
- by health care providers to identify other health care providers in health care transactions or on related correspondence;
- by health care providers on prescriptions (however, the NPI will not replace requirements for the Drug Enforcement Administration number or State license number);
- by health plans in their internal provider files to process transactions and communicate with health care providers;
- by health plans to coordinate benefits with other health plans;
- by health care clearinghouses in their internal files to create and process standard transactions and to communicate with health care providers and health plans;
- by electronic patient record systems to identify treating health care providers in patient medical records;
- by the Department of Health and Human Services to cross reference health care providers in fraud and abuse files and other program integrity files;
- for any other lawful activity requiring individual identification
The NPI number can be obtained online through the National Plan and Provider Enumeration System (NPPES) pages on CMS's website. Turnaround time for obtaining a number is from 1 to 20 days. NPI numbers can be searched on the CMS website listed in external links 'National Plan and Provider Enumeration System information from CMS'.
The NPI was proposed as an 8-position alphanumeric identifier. However, many stakeholders preferred a 10-position numeric identifier with a check digit in the last position (the first 9 positions are the identifier and the last position is a check digit) to help detect keying errors. The NPI contains no embedded intelligence; that is, it contains no information about the health care provider, such as the type or location of the health care provider.
An NPI number that is a 10-digit NPI Number may be validated using the Luhn algorithm by prefixing "80840" to the 10-digit number.
Open Data Set
NPI data is downloadable from CMS, the download (Which has been updated monthly until Dec 2012, from which point weekly differentials became available) includes a data structure file, this file is separately available from CMS. and details exactly what the file structure is. As of October 15, 2014 the file download size is 462 MB, and when extracted is over 4 GB.
Use as a data key
The NPI is a data key that identifies a substantial portion of healthcare providers and other entities in the US, it is a frequently used data key in other data sources. For instance, the DocGraph data set is a crowdfunded open data set that details how healthcare providers collaborate to deliver care (i.e. referral patterns) that uses the NPI as its data key.
- Centers for Medicare & Medicaid Services (CMS): HIPAA - General Information Retrieved 15 August 2006
- Centers for Medicare & Medicaid Services (CMS): National Plan and Provider Enumeration System (NPPES) National Provider Identifier (NPI) for Health Care Providers Retrieved 14 February 2007
- National Plan and Provider Enumeration System (NPPES) Data Dissemination – Readme 
- MedStartr Crowdfunding page for DocGraph
- O'Reilly Radar article on the structure of the DocGraph data set