Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

William L Tanzer, O.D.

Optometrist in Burlington, MA · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1649379082

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Registry record

Entity type Individual (Type 1)

Name William L Tanzer

Credential O.D.

Sex Male

Practice address Lahey Clinic, 41 Mall Road, Burlington, MA, 01805

Phone (781) 744-8000

Fax (781) 744-2540

Enumeration date Sep 22, 2006

Last updated in NPPES Oct 24, 2011

Taxonomy & licenses

152W00000X Optometrist Eye and Vision Services Providers · License 2744 (MA) Primary

OD · Doctor of Optometry: A licensed optometrist providing primary vision care, eye exams, and corrective lenses. About the OD credential

Other identifiers

Identifier	Type	State	Issuer
0336181	Medicaid	MA	-

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

How do I verify William Tanzer's NPI record?

Cross-check NPI 1649379082 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Is NPI 1649379082 active?

Yes, as of the latest NPPES snapshot, NPI 1649379082 is active (record last updated 2011-10-24).

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2011-10-24.