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

Alden G Gagnon, M.D.

Hematology (Internal Medicine) Physician in Chelmsford, MA · enumerated 2006 · practices at Spyridon Kantas MD PC.

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

National Provider Identifier

1912966011

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Registry record

Entity type Individual (Type 1)
Name Alden G Gagnon
Credential M.D.
Sex Male
Practice address Chelmsford, MA, 01824
Phone (978) 256-4121
Fax (978) 250-3210
Enumeration date Mar 20, 2006
Last updated in NPPES Sep 11, 2025

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 29255 (MA) Secondary
207RH0000X Hematology (Internal Medicine) Physician Allopathic & Osteopathic Physicians · License 29255 (MA) 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
709837 Other MA TUFTS HEALTH PLAN
99390801 Other MA NETWORK HEALTH
60521 Other NH HEALTHSOURCE
20696 Other MA FALLON COMM HEALTH PLAN
B13017 Other MA BCBS
30006380 Medicaid NH -
0130249 Medicaid MA -
3000077 Other MA UNITED HEALTHCARE
64833 Other MA HARVARD PILGRIM

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 Alden Gagnon?
Alden Gagnon is registered in NPPES with the primary taxonomy of Hematology (Internal 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 2025-09-11.