The NPI has replaced the Unique Physician 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).
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."
Individual HIPAA–covered healthcare providers include physicians, pharmacists, physician assistants, midwives, nurse practitioners, nurse anesthetists, dentists, denturists, licensed opticians, optometrists, chiropractors, clinical social workers, professional counselors, physical therapists, occupational therapists, prosthetists, orthotists, pharmacy technicians and athletic trainers.
This means that the numbers do not carry other information about healthcare providers, such as the state in which they live or their medical specialty.
[12] As another example, a subset of the crosswalk between EIN and NPI can be derived by analyzing the provider reference files from various payers.