What Is an NPI Number? Complete Guide to National Provider Identifiers

A National Provider Identifier (NPI) is a unique 10-digit number used to identify health care providers in standard health care transactions. The NPI was adopted as part of the administrative simplification provisions of the Health Insurance Portability and Accountability Act (HIPAA) and provides a standardized way to identify health care providers when exchanging health care information.

NPIs are assigned through the National Plan and Provider Enumeration System (NPPES) and are used throughout health care for activities such as claims, eligibility, claim status, referrals and other administrative transactions.

What Is the Purpose of an NPI Number?

The purpose of the NPI is to provide a standard identifier for health care providers. Before the NPI standard was implemented, providers could be assigned different identification numbers by different health plans and other organizations.

Using a standardized provider identifier helps health plans, clearinghouses and health care providers consistently identify the provider involved in an electronic health care transaction.

For example, an NPI may be used to identify a provider when submitting a health care claim, checking eligibility, requesting claim status information or exchanging other HIPAA standard transactions.

What Information Is Contained in an NPI Number?

The 10 digits of an NPI do not contain information about the health care provider. CMS describes the NPI as an intelligence-free numeric identifier.

This means you cannot determine information such as the following simply by examining the digits of an NPI:

• The provider's name
• The provider's specialty or taxonomy
• The provider's practice location
• Whether the provider is an individual or organization
• The state in which the provider practices

Instead, information associated with an NPI is maintained in NPPES. You can use the Eclaims NPI Lookup to search publicly available NPI information by NPI number, provider name, organization and other available search criteria.

Although taxonomy information is not contained within the NPI digits, one or more taxonomy codes can be associated with a provider's NPPES record to describe the provider's classification or specialization. Learn more in NPI Taxonomy Codes Explained.

Who Needs an NPI?

Health care providers that are covered entities under HIPAA must obtain an NPI and use the NPI in applicable HIPAA standard transactions. Health care providers that are not HIPAA-covered entities may also be eligible to obtain an NPI.

Providers that obtain NPIs fall into two primary entity types:

Understanding the distinction between an individual and an organization becomes especially important when determining which NPI should be reported for different provider roles on a health care claim. Learn more about the differences between NPI Type 1 and Type 2, including sole proprietors, incorporated providers and organization subparts.

Note: Organization health care providers may also have certain subparts that obtain their own NPIs. The rules surrounding individuals, organizations and subparts will be covered in more detail throughout this NPI article series.

How Are NPI Numbers Used in Health Care Claims?

NPIs are an important part of identifying the health care providers involved with a claim. A single claim may contain more than one NPI because different providers or organizations may perform different roles in the billing process.

Depending on the claim and circumstances, provider roles can include:

• Billing provider
• Rendering provider
• Referring provider
• Ordering provider
• Supervising provider
• Service facility

The appropriate NPI must be associated with the correct provider role. For professional claims, these relationships can also be represented on the CMS-1500 claim form and within the corresponding ANSI X12 837P electronic claim.

This is one reason an NPI should not be viewed simply as a provider number. Understanding which provider the NPI identifies and the role that provider performs can be important when preparing, reviewing or troubleshooting a health care claim.

Does an NPI Prove That a Provider Is Licensed or Credentialed?

No. The issuance of an NPI does not by itself validate that a health care provider is licensed, credentialed or approved to participate with a particular health plan.

An NPI also does not:

• Guarantee payment of a health care claim.
• Indicate that a provider participates with a particular health plan or network.
• Identify the provider's specialty from the digits of the NPI itself.
• Replace payer enrollment, credentialing or other program-specific requirements.

The NPI is primarily an identifier. Additional information associated with the provider, such as taxonomy and practice location information, is maintained separately from the 10-digit identifier.

Does an NPI Number Change?

An NPI is intended to be a lasting identifier. A provider generally keeps the same NPI when information such as the provider's name, address or taxonomy changes. Instead of obtaining a new NPI simply because this information changes, the provider's NPPES record should be kept current.

There are circumstances in which a new NPI may be appropriate, particularly for organizations and organizational changes. These situations should be evaluated using current CMS and NPPES guidance.

For more information about when an individual or organization may be associated with multiple NPIs, including Type 1 and Type 2 NPIs and organization subparts, see Can a Provider Have More Than One NPI?

An NPI does not expire, although it can be deactivated and later reactivated when appropriate. For more information about NPI status and what happens when provider information changes, see Does an NPI Expire? NPI Changes, Deactivation and Reactivation.

How Do I Apply for an NPI?

CMS provides several methods for obtaining an NPI. The most common is to apply electronically through the National Plan and Provider Enumeration System (NPPES).

NPPES is the system used to assign NPIs and maintain information associated with health care providers that have been enumerated.

How Do I Update My NPI Information?

Providers can use NPPES to maintain information associated with their NPI. Keeping information such as provider names, addresses and taxonomy information current helps ensure that the provider's NPPES record accurately reflects the information submitted by the provider.

How Can I Look Up an NPI Number?

NPPES provider information that is available for public disclosure can be used to search for and identify health care providers.

Searching by additional criteria can be particularly helpful when multiple providers have similar names or when you need to distinguish between an individual provider and an organization.

How Can I Check Whether a Number Is a Valid NPI?

The final digit of an NPI is a check digit calculated using the ISO standard Luhn algorithm. This allows the structure of an NPI number to be mathematically validated.

You can use the Eclaims NPI Validation Tool to check whether a number passes the NPI check-digit calculation.

Important: Passing the mathematical validation does not establish that the NPI is currently assigned to a particular provider or that the provider is licensed or credentialed. Use an NPI lookup when you need to review available provider information associated with an NPI.

How Is the NPI Check Digit Calculated?

The NPI check digit is calculated using the ISO standard Luhn algorithm, a modulus 10 calculation. Eclaims provides a step-by-step explanation in How to Calculate the NPI Check Digit.

NPI Numbers and Provider Identification

The NPI created a standardized way to identify health care providers in HIPAA standard transactions, but correctly using an NPI still requires understanding the provider behind the number and the role that provider performs.

Throughout this series, we'll take a closer look at individual and organization NPIs, provider roles, taxonomy codes and how NPIs are used on professional health care claims.

Supporting NPI Resources

• NPI Type 1 vs. Type 2: What's the Difference?
• How to Look Up an NPI Number
• NPI Taxonomy Codes Explained
• Can a Provider Have More Than One NPI?
• NPI vs. PTAN: What's the Difference?
• NPI Numbers on the CMS-1500 Claim Form
• Does an NPI Expire? NPI Changes, Deactivation and Reactivation
• NPI Lookup
• NPI Validation Tool
• How to Calculate the NPI Check Digit