Karthikeyan Viswanathan, DO

Primary specialty

Internal Medicine PhysicianTaxonomy code 207R00000X

License

20A19044 Issued in CA

Practice address

4546 El Camino Real Ste B7
Los Altos, CA 94022-1069

Phone

(866) 362-4246

Fax

(650) 260-6030

NPI assigned

Jul 8, 2015

Last updated

Aug 21, 2025By the provider in NPPES

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 MP, TX, CA4 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 4

Specialty

Internal Medicine

Education

Other, 2014

Medicare assignment

May accept Medicare assignment

Practice addresses (Care Compare)

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Osteopathy

State licenses

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: kviswanathan775373@direct.ochin.org

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

• Integrative Behavioral Health & Medicine, Inc.

  • Psychiatry Physician
  • Los Altos, CA
  • NPI 1548910151

  Internal Medicine

  Medicare reassignment NPD
• Round Valley Indian Health Center, Inc.

  • Clinic/Center
  • Covelo, CA
  • NPI 1669532750
  Medicare reassignment NPD
• Southern Humboldt Community Healthcare District

  dba Jerold Phelps Community Hospital

  • Critical Access Hospital
  • Garberville, CA
  • NPI 1003819376
  Medicare reassignment NPD
• United Indian Health Services, Inc.

  • Primary Care Clinic/Center
  • Arcata, CA
  • NPI 1497751572
  Medicare reassignment NPD
• DHHS, PHS, Naihs, Shiprock Hospital

  dba Northern Navajo Medical Center

  • General Acute Care Hospital
  • Shiprock, NM
  • NPI 1780639971

  TX

  Medicare reassignment NPD
• Sagan Hinemlo' Family Clinic, LLC

  • Health Service Clinic/Center
  • Saipan, MP
  • NPI 1396017489
  Medicare reassignment NPD
• Center for Cardiovascular Care a Medical Corporation

  • Interventional Cardiology Physician
  • San Jose, CA
  • NPI 1518977958
  NPD
• Redwoods Rural Health Center Inc.

  • Community Health Clinic/Center
  • Redway, CA
  • NPI 1235206087
  NPD
• Southern Humboldt Community Healthcare District

  dba Southern Humboldt Community Clinic

  • Rural Health Clinic/Center
  • Garberville, CA
  • NPI 1336367515
  NPD
• Southern Humboldt Community Healthcare District

  • Optometrist
  • Fortuna, CA
  • NPI 1952198012
  NPD
• United Indian Health Services, Inc.

  • Community Health Clinic/Center
  • Arcata, CA
  • NPI 1699506121
  NPD
• DHHS, PHS, Naihs, Shiprock Hospital

  • General Acute Care Hospital
  • Teec Nos Pos, AZ
  • NPI 1477615789
  NPD

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

{
    "created_epoch": "1436313600000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1755734400000",
    "number": "1396128336",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "4546 EL CAMINO REAL STE B7",
            "city": "LOS ALTOS",
            "state": "CA",
            "postal_code": "940221069",
            "telephone_number": "866-362-4246",
            "fax_number": "650-260-6030"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "4546 EL CAMINO REAL STE B7",
            "city": "LOS ALTOS",
            "state": "CA",
            "postal_code": "940221069",
            "telephone_number": "866-362-4246",
            "fax_number": "650-260-6030"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "VISWANATHAN",
        "first_name": "KARTHIKEYAN",
        "name_prefix": "Dr.",
        "credential": "DO",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2015-07-08",
        "last_updated": "2025-08-21",
        "certification_date": "2025-08-21",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207R00000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine",
            "state": "CA",
            "license": "20A19044",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": []
}

• Gwenaelle Jeanne Vezin, RD
• Diego Antonio Villarroel
• Jordan Alexus Vine
• Brenda Johanson Vinnicombe, OTR/L
• Divya Rathna Viswanathan, M.D.
• Catherine Vo
• Marianne Von Michalofski
• Siavosh Vossough, M.D.
• Elinor Eugenia Wahrmann, LMFT
• Yolanda Wai

• Internal Medicine Physician in Los Altos, CA
• Providers in Los Altos, CA by specialty
• Internal Medicine Physician in California

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Aug 21, 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.