NPI Portal NPI Lookup & Verification

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

Mark Pirner, MD

Internal Medicine Physician in Newtown, CT · enumerated 2012.

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

National Provider Identifier

1538439690

Verified

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Registry record

Entity type Individual (Type 1)
Name Mark Pirner
Credential MD
Sex Male
Practice address Newtown, CT, 06470
Phone (475) 323-7210
Enumeration date Jan 6, 2012
Last updated in NPPES Apr 8, 2022

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

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 52665 (CT) 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
NONE Other - NONE

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

What is the NPI number for Mark Pirner?
The National Provider Identifier (NPI) for Mark Pirner is 1538439690, a Type 1 (individual) record in the CMS NPPES registry.
Where does Mark Pirner practice?
The practice location on file with NPPES is in Newtown, CT. Providers can have multiple locations; NPPES lists the primary practice address.

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2022-04-08.