Cassidy Grieco

Primary specialty

Physician AssistantTaxonomy code 363A00000X

Practice address

133 Brookline Ave
Boston, MA 02215-3904

Phone

(617) 421-1000

NPI assigned

Apr 23, 2021

Sex

Female

Sole proprietor

No

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

Specialties & licenses 2

Addresses

Other names 1

• Cassidy Youngberg Former name

Medicare fee-for-service enrollment

Enrolled in MA

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: No

Green means eligible to order or refer.

Enrollment records 1

Specialty

Physician Assistant

Education

Tufts University School of Medicine, 2022

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Telehealth

Offers telehealth services

Group practices

Atrius Health IncGroup PAC ID 4789588641, 1,214 clinicians

Practice addresses (Care Compare)

Medicare enrollment (NPD)

Enrolled

Credentials

Physician Assistant

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: cyoungbergpa347484@direct.atrius.masshiway.net

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.

• Atrius Health, Inc.

  • Internal Medicine Physician
  • Boston, MA
  • NPI 1871639914
  Medicare reassignment Care Compare group
• Atrius Health, Inc.

  • Internal Medicine Physician
  • Needham, MA
  • NPI 1053862045
  NPD
• Atrius Health, Inc.

  • Internal Medicine Physician
  • Beverly, MA
  • NPI 1114265634

  Physician Assistant

  NPD

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

{
    "created_epoch": "1619136000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1763596800000",
    "number": "1306428941",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "133 BROOKLINE AVE",
            "city": "BOSTON",
            "state": "MA",
            "postal_code": "022153904",
            "telephone_number": "617-421-1000"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "133 BROOKLINE AVE",
            "city": "BOSTON",
            "state": "MA",
            "postal_code": "022153904",
            "telephone_number": "617-421-1000"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "GRIECO",
        "first_name": "CASSIDY",
        "sole_proprietor": "NO",
        "sex": "F",
        "enumeration_date": "2021-04-23",
        "last_updated": "2025-11-20",
        "certification_date": "2025-11-20",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "390200000X",
            "taxonomy_group": "",
            "desc": "Student in an Organized Health Care Education/Training Program",
            "state": null,
            "license": null,
            "primary": false
        },
        {
            "code": "363A00000X",
            "taxonomy_group": "",
            "desc": "Physician Assistant",
            "state": null,
            "license": null,
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": [
        {
            "first_name": "CASSIDY",
            "last_name": "YOUNGBERG",
            "credential": "PA",
            "code": "1",
            "type": "Former Name"
        }
    ]
}

• Samuel Ellis Grewe, MD
• Claire Leeann Greydanus, MD
• Katherine Bates Gribbons, MD
• Marissa Griecci, CRNA
• Melissa Grieco-Waters, MSW
• Julie A Grieco, PSYD
• Peter Charles Grieco, D.D.S.
• Holcombe E Grier, MD
• Dustin Shahab Griesemer, MD, PHD
• Susan Catherine Griever, NP

• Physician Assistant in Boston, MA
• Providers in Boston, MA by specialty
• Physician Assistant in Massachusetts

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Nov 20, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.