Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
John Victor Gahagan, M.D.
Surgery Physician in Pleasanton, CA · enumerated 2012.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1558629493
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Registry record
Entity type Individual (Type 1)
Name John Victor Gahagan
Credential M.D.
Sex Male
Practice address 5725 W Las Positas Blvd Ste 100, Pleasanton, CA, 94588
Phone (925) 734-8130
Enumeration date Apr 29, 2012
Last updated in NPPES Jun 11, 2024
Taxonomy & licenses
MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure.
About the MD 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.
Frequently asked questions
Is NPI 1558629493 active?
Yes, as of the latest NPPES snapshot, NPI 1558629493 is active (record last updated 2024-06-11).
How do I verify John Gahagan's NPI record?
Cross-check NPI 1558629493 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Other providers at this practice address
Browse all → Ruby Maini Medical Oncology Physician · Pleasanton, CA NPI 1063906063 Sadaf Nagshbandi Physician Assistant · Pleasanton, CA NPI 1386398857 Shannon George Physician Assistant · Pleasanton, CA NPI 1487388823 Sanna Daqiq Physician Assistant · Pleasanton, CA NPI 1730926858 Akhil Mehta Medical Oncology Physician · Pleasanton, CA NPI 1588293708
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-06-11.