NPIMap

Organization Active NPI

Unilab Corporation

Doing business as Quest Diagnostics

  • Clinical Medical Laboratory
  • West Hills, CA
National Provider Identifier
1366479099
Registry record updated Sep 16, 2026
On this page

Key facts

NPPES NPI Registry
Primary specialty
Clinical Medical LaboratoryTaxonomy code 291U00000X
License
05D0642827 Issued in CA
Legal business name
UNILAB CORPORATION
Doing business as
Quest Diagnostics
Practice address
8401 Fallbrook Ave
West Hills, CA 91304-3226
Phone
(800) 877-2515
NPI assigned
Jun 27, 2006
Last updated
Sep 16, 2026By the provider in NPPES
Organization subpart
Yes
Parent organization
QUEST DIAGNOSTICS INCORPORATEDAs reported in NPPES

NPPES NPI Registry

Updated by the provider on Sep 16, 2026

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

Authorized official

Name
Leah D Timmerman
Title
Vice President
Phone
(973) 520-2700

Specialties & licenses 1

Specialty (taxonomy)CodeLicenseStatePrimary
Clinical Medical Laboratory 291U00000X 05D0642827 CA Primary

Addresses

Primary practice location

8401 Fallbrook Ave
West Hills, CA 91304-3226

Mailing address

4770 Regent Blvd
Irving, TX 75063-2445
Phone (866) 697-8378

Other names 1

  • Quest Diagnostics Doing business as

Medicare participation

Medicare enrollment files
Medicare fee-for-service enrollment
Enrolled in CA

Enrollment records 1

Enrollment IDStateProvider typePAC IDDetails
O20040204001064 CA Part B Supplier - Independent Clinical Laboratory 7618874512 16 other NPIs on this enrollment
Practice locations: Arcadia, CA; Orange, CA; Redlands, CA; San Diego, CA; Ventura, CA; West Hills, CA

Other NPIs with the same Medicare PAC ID 3

NPIs whose Medicare enrollments share a PECOS associate control ID (the same enrolled entity).

Other NPIs on the same Medicare enrollment 13

NPIs listed together on one Medicare enrollment, typically parts of the same organization.

View all 13

Laboratory certificates & supplier records

Derived by NPIMap

These CMS records do not include an NPI. They are shown because their name and street address match this provider’s.

CLIA laboratory certificates

CLIA numberLaboratoryCertificateExpires
05D0642827Quest Diagnostics8401 Fallbrook Ave, West Hills, CA 91304AccreditationFeb 27, 2027

National Provider Directory

National Provider Directory
Tax ID family
Quest Diagnostics Incorporated22 organizations share this tax ID, including this one
Part of
Corning Lab Servicesinc

Other organizations with this tax ID 21

Organizations that report the same tax identification number in the National Provider Directory.

View all 21

Locations (25 of 50)

500 S Anaheim Hills Rd
Ste 121
Anaheim, CA 92807
Phone (310) 445-2951

701 Highland Springs Ave
Ste 6
Beaumont, CA 92223
Phone (909) 769-0300

8501 Wilshire Blvd
Ste 305
Beverly Hills, CA 90211

500 Paseo Camarillo
Ste 103
Camarillo, CA 93010

5800 Santa Rosa Rd
Ste 105
Camarillo, CA 93012

3439 Via Montebello
Carlsbad, CA 92009
Phone (760) 633-0168

4028 Grand Ave
Ste B
Chino, CA 91710

5562 Philadelphia St
Ste 206
Chino, CA 91710

480 Fourth Ave
Ste 101
Chula Vista, CA 91910

2071 Compton Ave
Ste 105A
Corona, CA 92881

750 N Diamond Bar Blvd
Ste 110
Diamond Bar, CA 91765

488 E Valley Pkwy
Ste 314
Escondido, CA 92025
Phone (760) 489-1458

521 E Elder St
Ste 201
Fallbrook, CA 92028
Phone (760) 723-7500

7390 Cherry Ave
Fontana, CA 92336
Phone (909) 428-3933

7880 Wren Ave
Ste A114
Gilroy, CA 95020

3600 N Verdugo Rd
Ste 303
Glendale, CA 91208

4477 W 118th St
Ste 102
Hawthorne, CA 90250

4050 Barranca Pkwy
Ste 120
Irvine, CA 92604

5103 Garfield St
La Mesa, CA 91941
Phone (619) 463-9917

78271 Highway 111
La Quinta, CA 92253
Phone (760) 564-2225

2650 Elm Ave
Ste 101
Long Beach, CA 90806

3816 Woodruff Ave
Ste 306
Long Beach, CA 90808

5830 Downey Ave
Long Beach, CA 90805

1127 Wilshire Blvd
Ste 203
Los Angeles, CA 90017

4520 W Sunset Blvd
Los Angeles, CA 90027
Phone (323) 662-2121

NPI Registry JSON

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

{
    "created_epoch": "1151366400000",
    "enumeration_type": "NPI-2",
    "last_updated_epoch": "1789516800000",
    "number": "1366479099",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "4770 REGENT BLVD",
            "city": "IRVING",
            "state": "TX",
            "postal_code": "750632445",
            "telephone_number": "866-697-8378"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "8401 FALLBROOK AVE",
            "city": "WEST HILLS",
            "state": "CA",
            "postal_code": "913043226",
            "telephone_number": "800-877-2515"
        }
    ],
    "practiceLocations": [],
    "basic": {
        "organization_name": "UNILAB CORPORATION",
        "organizational_subpart": "YES",
        "parent_organization_legal_business_name": "QUEST DIAGNOSTICS INCORPORATED",
        "enumeration_date": "2006-06-27",
        "last_updated": "2026-09-16",
        "certification_date": "2026-09-16",
        "status": "A",
        "authorized_official_last_name": "TIMMERMAN",
        "authorized_official_first_name": "LEAH",
        "authorized_official_middle_name": "D",
        "authorized_official_title_or_position": "VICE PRESIDENT",
        "authorized_official_telephone_number": "973-520-2700"
    },
    "taxonomies": [
        {
            "code": "291U00000X",
            "taxonomy_group": "",
            "desc": "Clinical Medical Laboratory",
            "state": "CA",
            "license": "05D0642827",
            "primary": true
        }
    ],
    "identifiers": [],
    "endpoints": [],
    "other_names": [
        {
            "organization_name": "Quest Diagnostics",
            "code": "3",
            "type": "Doing Business As"
        }
    ]
}

Other providers in West Hills, CA

Sources for this page

  • NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Sep 16, 2026; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
  • Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments.
  • 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.