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Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. John Stephen Hammes, M.D.

Nephrology Physician in San Diego, CA · enumerated 2006.

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

National Provider Identifier

1891766994

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Registry record

Entity type Individual (Type 1)
Name Dr. John Stephen Hammes
Credential M.D.
Sex Male
Practice address 8885 Rio San Diego Dr Ste 212, San Diego, CA, 92108
Phone (619) 299-2350
Fax (619) 297-8379
Enumeration date Jan 28, 2006
Last updated in NPPES Jun 15, 2026

Taxonomy & licenses

207RN0300X Nephrology Physician Allopathic & Osteopathic Physicians · License G84351 (CA) Primary
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

Other identifiers

Identifier Type State Issuer
CB204086 Other CA SO CA MEDICARE PTAN
G84351 Other CA CA LICENSE
CA125550 Other CA NO CA MEDICARE PTAN

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 Hammes's NPI record?
Cross-check NPI 1891766994 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Is NPI 1891766994 active?
Yes, as of the latest NPPES snapshot, NPI 1891766994 is active (record last updated 2026-06-15).

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-06-15.