NPIMap

Individual provider Active NPI

Kristen Lynn Zack, MD

  • Nephrology Physician
  • Billings, MT
National Provider Identifier
1376105692
Registry record updated Aug 28, 2025
On this page

Key facts

NPPES NPI Registry
Primary specialty
Nephrology PhysicianTaxonomy code 207RN0300X
License
162224 Issued in MT
Practice address
1045 N 30TH St
Billings, MT 59101-0733
Phone
(406) 238-2500
NPI assigned
Jul 8, 2019
Sex
Female
Sole proprietor
No

NPPES NPI Registry

Updated by the provider on Aug 28, 2025

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

Specialties & licenses 1

Specialty (taxonomy)CodeLicenseStatePrimary
Nephrology Physician 207RN0300X 162224 MT Primary

Addresses

Primary practice location

1045 N 30TH St
Billings, MT 59101-0733

Mailing address

1045 N 30TH St
Billings, MT 59101-0733
Phone (406) 238-2500

Other names 1

  • Kristen Lynn Pietrzyk Former name

Medicare participation

Medicare enrollment files
Medicare fee-for-service enrollment
Enrolled in MT, WY2 enrollments
Eligible to order & refer
  • Part B services
  • Medical equipment
  • Home health
  • Power mobility devices
  • Hospice
Green means eligible to order or refer.

Enrollment records 2

Enrollment IDStateProvider typePAC IDDetails
I20250912001092 MT Practitioner - Nephrology 7012245475 Reassigns benefits to 1 organization
I20260109001838 WY Practitioner - Nephrology 7012245475 Reassigns benefits to 1 organization

Care Compare profile

Medicare Care Compare
Specialty
Nephrology
Education
Other, 2019
Medicare assignment
Accepts the Medicare-approved amount as payment in full
Group practices
Billings ClinicGroup PAC ID 6002993516, shared by 7 NPIs, 814 clinicians

Practice addresses (Care Compare)

201 Yellowstone Ave
Cody, WY 82414-9313
Phone (307) 527-7561

801 N 29TH St
Billings, MT 59101-0905
Phone (406) 238-2500

Hospital & facility affiliations

  • Billings Clinic Hospital Hospital, Billings, MT, CCN 270004
  • Sheridan Memorial Hospital Hospital, Sheridan, WY, CCN 530006
  • Glendive Medical Center Hospital, Glendive, MT, CCN 271332
  • Johnson County Healthcare Center Hospital, Buffalo, WY, CCN 531308
  • Sidney Health Center Hospital, Sidney, MT, CCN 271344

National Provider Directory

National Provider Directory
Medicare enrollment (NPD)
Enrolled
Credentials
Doctor of Medicine

State licenses

LicenseStateTypeSpecialty
162224MTMDNephrology Physician

Practice roles

OrganizationSpecialtyStatusNew patients
Billings Clinic CurrentSince Dec 1, 2025 Accepting new patients
Billings Cinic CurrentSince Aug 28, 2025 Accepting new patients
Billings Clinic Nephrology CurrentSince Aug 28, 2025 Accepting new patients
Billings Clinic Current Accepting new patients
Billings Clinic Past Accepting new patients
Regents of the Univ of Ca Past Accepting new patients

Locations

2800 10th Ave N
Billings, MT 59101
Phone (406) 248-3290

1045 N 30th St
Billings, MT 59101
Phone (406) 238-2501

801 N 29th St
Billings, MT 59101
Phone (406) 238-2210

201 Yellowstone Ave
Cody, WY 82414
Phone (307) 527-7561

707 Sheridan Ave
Cody, WY 82414
Phone (307) 527-7561

Interoperability endpoints

  • Direct secure messaging: kpietrzyk731262@direct.med.utah.edu

Organizations & group practices 6

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.

Hospital & facility affiliations 13

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

View all 13

NPI Registry JSON

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

{
    "created_epoch": "1562544000000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1756339200000",
    "number": "1376105692",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "1045 N 30TH ST",
            "city": "BILLINGS",
            "state": "MT",
            "postal_code": "591010733",
            "telephone_number": "406-238-2500"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "1045 N 30TH ST",
            "city": "BILLINGS",
            "state": "MT",
            "postal_code": "591010733",
            "telephone_number": "406-238-2500"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "last_name": "ZACK",
        "first_name": "KRISTEN",
        "middle_name": "LYNN",
        "credential": "MD",
        "sole_proprietor": "NO",
        "sex": "F",
        "enumeration_date": "2019-07-08",
        "last_updated": "2025-08-28",
        "certification_date": "2025-08-28",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207RN0300X",
            "taxonomy_group": "",
            "desc": "Internal Medicine, Nephrology",
            "state": "MT",
            "license": "162224",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": [
        {
            "first_name": "KRISTEN",
            "last_name": "PIETRZYK",
            "middle_name": "LYNN",
            "code": "1",
            "type": "Former Name"
        }
    ]
}

Other providers in Billings, MT

Sources for this page

Verify at the official NPI Registry.