Alexander William Threlfall, MD

Primary specialty

Psychiatry PhysicianTaxonomy code 2084P0800X

License

113086 Issued in CA

Practice address

800 A St
San Rafael, CA 94901-3011

Phone

(415) 457-8182

Fax

(415) 457-7471

NPI assigned

Dec 29, 2006

Sex

Male

Sole proprietor

No

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

Specialties & licenses 1

Addresses

Medicare fee-for-service enrollment

Enrolled in CA2 enrollments

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 2

Specialty

PsychiatryAlso: Geriatric Psychiatry

Education

Other, 2006

Medicare assignment

May accept Medicare assignment

Telehealth

Offers telehealth services

Group practices

Regents Univ of California UCSFGroup PAC ID 6305160300, 276 clinicians

Santa Rosa Community Health CentersGroup PAC ID 0345130423, shared by 5 NPIs, 69 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• Marinhealth Medical Center Hospital, Greenbrae, CA, CCN 050360

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: athrelfall16226@direct-ucsfmedicalcenter.org

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.

• Regents Univ of California UCSF

  • Internal Medicine Physician
  • San Francisco, CA
  • NPI 1124439807

  Psychiatry

  Medicare reassignment Care Compare group NPD
• Ritter Center

  • Federally Qualified Health Center (FQHC)
  • San Rafael, CA
  • NPI 1417370032
  Medicare reassignment NPD
• Santa Rosa Community Health Centers

  • Federally Qualified Health Center (FQHC)
  • Santa Rosa, CA
  • NPI 1578631172
  Medicare reassignment NPD
• Santa Rosa Community Health Centers

  • Federally Qualified Health Center (FQHC)
  • Santa Rosa, CA
  • NPI 1386712065
  NPD
• Santa Rosa Community Health Centers

  • Federally Qualified Health Center (FQHC)
  • Santa Rosa, CA
  • NPI 1467180430
  NPD
• Agewell Pace

  • General Practice Physician
  • Rohnert Park, CA
  • NPI 1437833597
  NPD (past)
• Santa Rosa Community Health Centers

  • Federally Qualified Health Center (FQHC)
  • Santa Rosa, CA
  • NPI 1629960174
  NPD (past)
• UCSF Psychiatry

  • Psychiatry Physician
  • San Francisco, CA
  • NPI 1427105279
  NPD (past)

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

• Marin General Hospital

  • General Acute Care Hospital
  • Greenbrae, CA
  • NPI 1396725677
  Care Compare affiliation

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

{
    "created_epoch": "1167350400000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1788220800000",
    "number": "1669538187",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "PO BOX 3517",
            "city": "SAN RAFAEL",
            "state": "CA",
            "postal_code": "949123517",
            "telephone_number": "415-457-8182",
            "fax_number": "415-457-7471"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "800 A ST",
            "city": "SAN RAFAEL",
            "state": "CA",
            "postal_code": "949013011",
            "telephone_number": "415-457-8182",
            "fax_number": "415-457-7471"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "THRELFALL",
        "first_name": "ALEXANDER",
        "middle_name": "WILLIAM",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2006-12-29",
        "last_updated": "2026-09-01",
        "certification_date": "2026-09-01",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "2084P0800X",
            "taxonomy_group": "",
            "desc": "Psychiatry & Neurology, Psychiatry",
            "state": "CA",
            "license": "113086",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Dean J Thompson, D.C.
• Emily Anne Thompson
• Annette S Thorn, MD MPH
• Deirdre Thorne-Hadfield, W.H.N.P. M.S. R.N.
• Chris Thorson
• Thrifty Payless Inc
• Thrifty Payless Inc
• Sophia Thurston
• Tom Thurston, M.F.T.
• Wayne Charles Thurston, PSY.D.

• Psychiatry Physician in San Rafael, CA
• Providers in San Rafael, CA by specialty
• Psychiatry Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 1, 2026; 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.