NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Calvin Tan, O.D.

Optometrist in Pasadena, CA · enumerated 2011 · practices at Linden Optometry A Professional Corporation.

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

National Provider Identifier

1043507643

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Registry record

Entity type Individual (Type 1)
Name Dr. Calvin Tan
Credential O.D.
Sex Male
Practice address Pasadena, CA, 91101
Phone (626) 796-1191
Fax (626) 796-0189
Enumeration date Jul 3, 2011
Last updated in NPPES Oct 24, 2021

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

152W00000X Optometrist Eye and Vision Services Providers · License 14313TLG (CA) Primary
OD · Doctor of Optometry: A licensed optometrist providing primary vision care, eye exams, and corrective lenses. About the OD credential

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

Is NPI 1043507643 active?
Yes, as of the latest NPPES snapshot, NPI 1043507643 is active (record last updated 2021-10-24).
How do I verify Calvin Tan's NPI record?
Cross-check NPI 1043507643 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2021-10-24.