Alden G Gagnon, M.D.

Primary specialty

Hematology (Internal Medicine) PhysicianTaxonomy code 207RH0000X

License

29255 Issued in MA

Practice address

23 Village SQ
Chelmsford, MA 01824-2712

Phone

(978) 256-4121

Fax

(978) 250-3210

NPI assigned

Mar 20, 2006

Sex

Male

Sole proprietor

Yes

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 2

Addresses

Other identifiers 9

Medicare fee-for-service enrollment

Not listed in the public Medicare enrollment file

Medicare enrollment (NPD)

Not enrolled

HHS exclusion list flag

Flagged The directory lists this NPI on an HHS exclusion list. The OIG exclusions file (LEIE) holds no record for this NPI, and the directory does not say which list the flag comes from. How exclusions are shown Confirm with the OIG exclusions search.

Credentials

Doctor of Medicine

State licenses

Practice roles

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships and National Provider Directory roles.

• Lowell Hematology and Oncology PC

  • Hematology & Oncology Physician
  • Lowell, MA
  • NPI 1225004211
  NPD (past)

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1142812800000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1757548800000",
    "number": "1912966011",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "PO BOX 1807",
            "city": "MERRIMACK",
            "state": "NH",
            "postal_code": "030541807",
            "telephone_number": "603-673-9411",
            "fax_number": "603-673-9899"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "23 VILLAGE SQ",
            "city": "CHELMSFORD",
            "state": "MA",
            "postal_code": "018242712",
            "telephone_number": "978-256-4121",
            "fax_number": "978-250-3210"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "GAGNON",
        "first_name": "ALDEN",
        "middle_name": "G",
        "credential": "M.D.",
        "sole_proprietor": "YES",
        "sex": "M",
        "enumeration_date": "2006-03-20",
        "last_updated": "2025-09-11",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207R00000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine",
            "state": "MA",
            "license": "29255",
            "primary": false
        },
        {
            "code": "207RH0000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine, Hematology",
            "state": "MA",
            "license": "29255",
            "primary": true
        }
    ],
    "identifiers": [
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "TUFTS HEALTH PLAN",
            "identifier": "709837",
            "state": "MA"
        },
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "NETWORK HEALTH",
            "identifier": "99390801",
            "state": "MA"
        },
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "HEALTHSOURCE",
            "identifier": "60521",
            "state": "NH"
        },
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "FALLON COMM HEALTH PLAN",
            "identifier": "20696",
            "state": "MA"
        },
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "BCBS",
            "identifier": "B13017",
            "state": "MA"
        },
        {
            "code": "05",
            "desc": "MEDICAID",
            "issuer": null,
            "identifier": "30006380",
            "state": "NH"
        },
        {
            "code": "05",
            "desc": "MEDICAID",
            "issuer": null,
            "identifier": "0130249",
            "state": "MA"
        },
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "UNITED HEALTHCARE",
            "identifier": "3000077",
            "state": "MA"
        },
        {
            "code": "01",
            "desc": "Other (non-Medicare)",
            "issuer": "HARVARD PILGRIM",
            "identifier": "64833",
            "state": "MA"
        }
    ],
    "endpoints": [],
    "other_names": []
}

• Larimar Fuentes, M.S.
• Kira P Furtado, LICSW
• Savannah Fyfe
• Noble Gabriel, M.D.
• Stephanie Gaeta, BCBA, LABA
• Buffy Marie Gamache, LICSW
• Gopi Garala
• Vivian Garcia, MED
• Gail Marie Gardetto, LICSW
• Lilia Gavrilov

• Hematology (Internal Medicine) Physician in Chelmsford, MA
• Providers in Chelmsford, MA by specialty
• Hematology (Internal Medicine) Physician in Massachusetts

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 11, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.