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Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

John J Mast, M.D.

Family Medicine Physician in Elizabethtown, PA · enumerated 2006 · practices at Lancaster General Medical Group.

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

National Provider Identifier

1154392371

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Registry record

Entity type Individual (Type 1)
Name John J Mast
Credential M.D.
Sex Male
Practice address 418 Cloverleaf Rd, Elizabethtown, PA, 17022
Phone (717) 653-1467
Fax (717) 653-1001
Enumeration date Jan 27, 2006
Last updated in NPPES Oct 25, 2007

Taxonomy & licenses

207Q00000X Family Medicine Physician Allopathic & Osteopathic Physicians · License MD066311L (PA) 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
01886502 Other PA CAPITAL BLUE CROSS
43009 S101 Other PA GEISINGER HEALTH PLAN
P002671 Other PA GATEWAY HEALTH PLAN
2149271 Other PA AETNA HMO
G79964 Other PA HEALTH ASSURANCE
516277 Other PA HIGHMARK BLUE SHIELD
5163765 Other PA AETNA NON-HMO
0017331020001 Medicaid PA -

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 this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.
What specialty is John Mast?
John Mast is registered in NPPES with the primary taxonomy of Family Medicine Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-10-25.