Gassan Kassim, MD

Primary specialty

Gastroenterology PhysicianTaxonomy code 207RG0100X

License

2025016144 Issued in MO

Practice address

1 Barnes Jewish Hospital PLZ
Div Im Gastroenterology
Saint Louis, MO 63110-1003

Phone

(314) 747-2066

Fax

(314) 362-2357

NPI assigned

Jul 8, 2018

Sex

Male

Sole proprietor

No

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

Specialties & licenses 2

Addresses

Electronic endpoints 1

Medicare fee-for-service enrollment

Enrolled in MO

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 1

Specialty

GastroenterologyAlso: Internal Medicine

Education

Other, 2016

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

Washington UniversityGroup PAC ID 9830008770, 2,968 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• Barnes Jewish Hospital Hospital, Saint Louis, MO, CCN 260032
• Barnes-Jewish West County Hospital Hospital, Creve Coeur, MO, CCN 260162
• Missouri Baptist Medical Center Hospital, Saint Louis, MO, CCN 260108

Procedures performed for Medicare patients

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

Practice roles

Locations

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.

• Washington University

  • Multi-Specialty Clinic/Center
  • Saint Louis, MO
  • NPI 1992746903
  Medicare reassignment Care Compare group NPD
• Washington University

  • Multi-Specialty Clinic/Center
  • Saint Louis, MO
  • NPI 1962442475
  NPD
• Washington University

  • Multi-Specialty Clinic/Center
  • Saint Louis, MO
  • NPI 1134169568
  NPD (past)
• Frances Mahon Deaconess Hospital

  • Critical Access Hospital
  • Glasgow, MT
  • NPI 1689685323
  NPD (past)

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

• Barnes Jewish Hospital

  • General Acute Care Hospital
  • Saint Louis, MO
  • NPI 1649299827
  Care Compare affiliation
• Barnes Jewish West County Hospital

  • General Acute Care Hospital
  • Saint Louis, MO
  • NPI 1831107895
  Care Compare affiliation
• Missouri Baptist Medical Center

  • General Acute Care Hospital
  • Saint Louis, MO
  • NPI 1487663506
  Care Compare affiliation

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

{
    "created_epoch": "1531008000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1752796800000",
    "number": "1396231890",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "PO BOX 7412011",
            "city": "CHICAGO",
            "state": "IL",
            "postal_code": "606742011",
            "telephone_number": "314-747-2066",
            "fax_number": "314-362-2357"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "1 BARNES JEWISH HOSPITAL PLZ",
            "address_2": "DIV IM GASTROENTEROLOGY",
            "city": "SAINT LOUIS",
            "state": "MO",
            "postal_code": "631101003",
            "telephone_number": "314-747-2066",
            "fax_number": "314-362-2357"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "KASSIM",
        "first_name": "GASSAN",
        "name_prefix": "Dr.",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "M",
        "enumeration_date": "2018-07-08",
        "last_updated": "2025-07-18",
        "certification_date": "2021-07-01",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207R00000X",
            "taxonomy_group": "",
            "desc": "Internal Medicine",
            "state": "MO",
            "license": "2025016144",
            "primary": false
        },
        {
            "code": "207RG0100X",
            "taxonomy_group": "",
            "desc": "Internal Medicine, Gastroenterology",
            "state": "MO",
            "license": "2025016144",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [
        {
            "endpointType": "FHIR",
            "endpointTypeDescription": "FHIR URL",
            "endpoint": "https://epicproxy.et0965.epichosted.com/FHIRProxy/api/FHIR/DSTU2/",
            "affiliation": "Y",
            "affiliationName": "Washington University",
            "address_1": "1 Barnes Jewish Hospital Plz",
            "address_2": "Div IM Gastroenterology",
            "city": "Saint Louis",
            "state": "MO",
            "country_code": "US",
            "postal_code": "631101003",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "other_names": []
}

• Thomas J Kasper, MD
• Michael A Kass, MD
• Jordan Kassab
• Aryn Kassel, NNP-BC
• Rachel Kassel, MD PHD
• Abigail Rehmer Kassing, PT
• Erin Kasson, BCBA, LBA
• Margean M Kastner, M.S.W.
• Hannah Kathryn Rose Kasunic, PA-C
• Nitika Kaswan, MD

• Gastroenterology Physician in Saint Louis, MO
• Providers in Saint Louis, MO by specialty
• Gastroenterology Physician in Missouri

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Jul 18, 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.