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

Dr. John A Chellsen, PH.D.

Clinical Psychologist in Stockton, CA · enumerated 2006 · practices at Imperial Transport Services LLC.

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

National Provider Identifier

1669403580

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Registry record

Entity type Individual (Type 1)
Name Dr. John A Chellsen
Credential PH.D.
Sex Male
Practice address Stockton, CA, 95207
Phone (209) 473-4211
Fax (209) 473-0610
Enumeration date Jul 6, 2006
Last updated in NPPES Jul 8, 2007

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

Taxonomy & licenses

103TC0700X Clinical Psychologist Behavioral Health & Social Service Providers · License PSY8979 (CA) Primary
PHD · Doctor of Philosophy: A doctoral degree; in healthcare often held by clinical psychologists and researchers. About the PHD 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

How do I verify John Chellsen's NPI record?
Cross-check NPI 1669403580 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Is NPI 1669403580 active?
Yes, as of the latest NPPES snapshot, NPI 1669403580 is active (record last updated 2007-07-08).

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.