Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Mr. Alan Lin

Specialist in San Francisco, CA · enumerated 2018.

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

National Provider Identifier

1639645781

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Registry record

Entity type Individual (Type 1)

Name Mr. Alan Lin

Sex Male

Practice address 1550 Treat Ave, San Francisco, CA, 94110

Phone (415) 641-8000

Enumeration date Oct 16, 2018

Last updated in NPPES Oct 16, 2018

Taxonomy & licenses

174400000X Specialist Other Service Providers Primary

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.

Read the full guide → Validate an NPI →

Frequently asked questions

Is NPI 1639645781 active?

Yes, as of the latest NPPES snapshot, NPI 1639645781 is active (record last updated 2018-10-16).

How do I verify Alan Lin's NPI record?

Cross-check NPI 1639645781 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 2018-10-16.