How do I check that an NPI is real?

Search the NPI at nppes.cms.hhs.gov or use Fonteum's NPI lookup at fonteum.com/tools/npi-lookup. A valid, active NPI will return a provider record with a name, enumeration date, and at least one taxonomy code. If the NPI returns no result, it was never issued or was deactivated. Invalid check digits will fail immediately.

What is the difference between an NPI lookup and a full NPI credential check?

An NPI lookup returns the NPPES record associated with a number — name, specialty, address. A broader credential check also consults OIG LEIE and Medicare enrollment data. It reports an exclusion no-match only when serving coverage reconciles to a current comparable attested artifact; stale coverage is indeterminate and is not a clearance. The credentialing decision remains yours.

Can an NPI be fake or invalid?

Yes, in two ways. A fabricated NPI that fails the Luhn check digit validation is structurally invalid — any NPI validator will catch this instantly. A structurally valid NPI (passes Luhn) that does not appear in NPPES was never issued or has been deactivated. Neither an invalid NPI nor an unassigned NPI should appear on a healthcare claim.

Is NPI validation free?

Yes. NPPES is a free federal public registry at nppes.cms.hhs.gov — no login or fee. The OIG exclusion list at oig.hhs.gov/exclusions is also free. CMS PECOS enrollment data is available via the Provider Enrollment, Chain and Ownership System and published as a public-use file. Fonteum's NPI lookup aggregates all three registries at no cost.

What does it mean if a provider's NPI is deactivated?

A deactivated NPI means the provider requested deactivation (typically upon retirement or death) or CMS administratively deactivated it for inactivity or fraud. Deactivated NPIs no longer appear as active in NPPES but remain in the historical record with a deactivation date. Claims submitted under a deactivated NPI will be rejected by Medicare and most commercial payers.

Fonteum · Learn · Updated 2026-06-06

How to Verify an NPI

Verify any NPI in 3 steps: look up the NPPES record at nppes.cms.hhs.gov, check CMS PECOS enrollment status, and cross-reference the OIG exclusion list. All three registries are free federal databases — no login, no fee. Takes under five minutes.

Source: NPPES · CMS PECOS · OIG LEIE · Public DomainUpdated 2026-06-06

The 3-step NPI validation process

Look up the NPPES record

Search the NPI at nppes.cms.hhs.gov or through Fonteum's lookup. Compare the submitted NPPES name, taxonomy, address, and enumeration status with your records. Do not treat a match as proof that an address, license, credential, or practice status is current; confirm those facts with the relevant primary authority.

Check CMS PECOS enrollment status

CMS PECOS (Provider Enrollment, Chain and Ownership System) tracks whether a provider is currently enrolled to bill Medicare or Medicaid. An NPI in NPPES does not automatically mean the provider is enrolled in Medicare. Search PECOS at pecos.cms.hhs.gov or through the public Ordering and Referring file on data.cms.gov.

Cross-reference the OIG LEIE exclusion list

The OIG List of Excluded Individuals and Entities (LEIE) lists providers and organizations excluded from participation in federal healthcare programs. Any provider on the LEIE is prohibited from billing Medicare and Medicaid. Search by NPI, name, or license number at oig.hhs.gov/exclusions or via Fonteum's sanctions lookup.

All three checks in one view

Fonteum's NPI lookup aggregates NPPES identity, PECOS enrollment status, and OIG exclusion status for any provider — searchable by NPI or name.

Open NPI Lookup →

What to look for in each registry

NPPES — what to check

Enumeration status: Active vs. Deactivated. An active NPI is in current use. A deactivated NPI should not appear on claims.
Name match: Confirm the legal name matches your records. Watch for maiden name vs. married name, middle name inclusion, and credential suffix variations (MD vs. M.D.).
Address currency: Providers are required to update NPPES within 30 days of an address change. A stale address may indicate an inactive practice location.
Taxonomy codes:Confirm the listed specialties match the services being billed. An NPI listed only as “Pharmacy” billing for physician services is a red flag.

PECOS — what to check

Enrollment status: Active enrollment means the provider is approved to bill Medicare/Medicaid. Not all providers in NPPES are enrolled in PECOS — an NPI is required to get a PECOS enrollment, but having an NPI does not mean the provider is enrolled.
Ordering/referring status: For providers who order tests or refer patients but do not themselves bill Medicare, enrollment in the ordering-and-referring file is required. Check the CMS Ordering and Referring file (data.cms.gov) separately.

OIG LEIE — what to check

Exclusion status: Search by NPI, provider name, or license number. Any match requires immediate action — employment of or contracting with an excluded provider exposes the employing entity to civil monetary penalties and repayment liability under current federal law.
Exclusion type: Mandatory exclusions (program conviction, patient abuse) and permissive exclusions (fraud, license revocation) carry different reinstatement paths. The LEIE record specifies the exclusion type.

Red flags when checking an NPI

NPI fails the Luhn check — it was never validly issued or was fabricated
NPI searches return no result — was never issued or was deactivated
Provider name in NPPES does not match the name on the credential or claim
Taxonomy codes listed do not match the services being billed or the specialty claimed
Provider appears on OIG LEIE — any match is a hard stop; do not employ, contract with, or submit claims for this provider
NPPES address is years out of date for a claimed active practice location
Provider claims active Medicare enrollment but does not appear in the CMS Ordering and Referring file or active PECOS enrollment

Frequently asked questions

How do I check that an NPI is real?: Search the NPI at nppes.cms.hhs.gov or use Fonteum's NPI lookup at fonteum.com/tools/npi-lookup. A valid, active NPI will return a provider record with a name, enumeration date, and at least one taxonomy code. If the NPI returns no result, it was never issued or was deactivated. Invalid check digits will fail immediately.
What is the difference between an NPI lookup and a full NPI credential check?: An NPI lookup returns the NPPES record associated with a number — name, specialty, address. A broader credential check also consults OIG LEIE and Medicare enrollment data. It reports an exclusion no-match only when serving coverage reconciles to a current comparable attested artifact; stale coverage is indeterminate and is not a clearance. The credentialing decision remains yours.
Can an NPI be fake or invalid?: Yes, in two ways. A fabricated NPI that fails the Luhn check digit validation is structurally invalid — any NPI validator will catch this instantly. A structurally valid NPI (passes Luhn) that does not appear in NPPES was never issued or has been deactivated. Neither an invalid NPI nor an unassigned NPI should appear on a healthcare claim.
Is NPI validation free?: Yes. NPPES is a free federal public registry at nppes.cms.hhs.gov — no login or fee. The OIG exclusion list at oig.hhs.gov/exclusions is also free. CMS PECOS enrollment data is available via the Provider Enrollment, Chain and Ownership System and published as a public-use file. Fonteum's NPI lookup aggregates all three registries at no cost.
What does it mean if a provider's NPI is deactivated?: A deactivated NPI means the provider requested deactivation (typically upon retirement or death) or CMS administratively deactivated it for inactivity or fraud. Deactivated NPIs no longer appear as active in NPPES but remain in the historical record with a deactivation date. Claims submitted under a deactivated NPI will be rejected by Medicare and most commercial payers.

NPI lookup tool — search by NPI or name; returns NPPES, PECOS, and OIG records.
What is an NPI number? — the full definitional explainer: who needs one, structure, and background.
NPI meaning — what the acronym stands for and what NPPES records contain.
OIG LEIE sanctions lookup — check if a provider is excluded from federal healthcare programs.
County-level nursing-home staffing deserts — an example of NPI-anchored federal data in action.

Reviewed by Jennifer Montecillo, MD, medical reviewer. Non-practicing medical reviewer. Review covered the accuracy of validation steps, regulatory references (NPPES, PECOS, OIG LEIE), and red-flag guidance. This page does not constitute legal or compliance advice; consult your compliance officer for program-specific requirements.

Fonteum Research Bureau. “How to Verify an NPI — Step-by-Step Guide.” 2026-06-06. Sources: NPPES (CMS / HRSA), CMS PECOS, OIG LEIE (oig.hhs.gov/exclusions). All registries free and public domain. Available at https://fonteum.com/learn/how-to-verify-an-npi.