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WESTSIDE INTERNAL MEDICINE
NPI 1184631251
Internal Medicine in Santa Monica, CA

Active since August 02, 2006CLIA 05D0550324 · Certificate of Compliance
2121 WILSHIRE BLVD, # 304, SANTA MONICA, CA 90403(310) 264-0065(310) 829-0765 Get Directions Write a Review

NPPES record last updated: November 26, 2025. Verified against the NPPES registry weekly; last sync: October 18, 2026.

Record update history: Nov 26, 2025, Nov 13, 2025 (2 updates tracked since 2025).

About Westside Internal Medicine NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

WESTSIDE INTERNAL MEDICINE (NPI 1184631251) is a healthcare organization registered as an internal medicine in Santa Monica, California and active in the NPI registry since August 2006. The organization holds a CLIA Certificate of Compliance certificate valid through September 13, 2027 and lists Ernie Prudente, Partner, as its authorized official.

NPPES Registry Identity

NPI1184631251
Entity TypeOrganization
Primary Taxonomy207R00000X
Legal Business NameWESTSIDE INTERNAL MEDICINE
Location Address2121 WILSHIRE BLVD, # 304Santa Monica, CA 90403
Mailing Address2121 Wilshire Blvd Ste 304Santa Monica, CA 90403-5743 · (310) 264-0065 · Fax (310) 829-0765
Phone(310) 264-0065
Fax(310) 829-0765
Organization SubpartNo
Authorized OfficialErnie PrudentePartner · (310) 829-7762
Enumeration DateAugust 2, 2006
Last NPPES UpdateNovember 26, 20252 updates tracked since enumeration
NPPES CertifiedNovember 26, 2025
✔ NPI 1184631251 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
Also ListedClinical Medical LaboratoryTaxonomy 291U00000X
2121 WILSHIRE BLVD, Santa Monica, CA 90403
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Medicare Participation & PECOS CMS

Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Westside Internal Medicine is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Clinicians Billing Medicare Through This Organization

9

Medicare enrollment records show 9 clinicians reassign Medicare billing to Westside Internal Medicine, which bills Medicare for the services they deliver. Of these, 9 practice at this address. They are listed nearest first.

Clinicians, nearest first (9)

John Andrews, M.D.
Internal Medicine
NPI 1447262126
2121 WILSHIRE BLVD STE 307
Santa Monica, CA 90403
(310) 264-0165
✔ PECOSSame address
Jonathan Barthelet
Internal Medicine
NPI 1811428550
2121 WILSHIRE BLVD STE 305
Santa Monica, CA 90403
(310) 264-0065
✔ PECOSSame address
Anushka Bhalla, MD, MPH
Family Practice
NPI 1558701284
2121 WILSHIRE BLVD # 300
Santa Monica, CA 90403
(310) 692-9772
✔ PECOSSame address
Teresa Dean, M.D.
Internal Medicine
NPI 1255538781
2121 WILSHIRE BLVD # 300
Santa Monica, CA 90403
(310) 695-2450
✔ PECOSSame address
Jamie Elson-Wolin, M.D.
Family Practice
NPI 1003109752
2121 WILSHIRE BLVD SUITE 306
Santa Monica, CA 90403
(310) 264-0765
✔ PECOSSame address
Joel Isackson, MD
Internal Medicine
NPI 1285640680
2121 WILSHIRE BLVD # 307
Santa Monica, CA 90403
(310) 264-0565
✔ PECOSSame address
Ernest Prudente, MD
Internal Medicine
NPI 1033136510
2121 WILSHIRE BLVD #306
Santa Monica, CA 90403
(310) 829-7762
✔ PECOSSame address
Jonathan Weaver, MD
Internal Medicine
NPI 1851318331
2121 WILSHIRE BLVD #103
Santa Monica, CA 90403
(310) 264-0065
✔ PECOSSame address
Mark Biscow, MD
Internal Medicine
NPI 1871510354
2121 WILSHIRE BLVD #305
Santa Monica, CA 90403
(310) 264-0065
✔ PECOSSame address

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

CLIA Laboratory Certificates CMS CLIA

Laboratory certificates issued under the Clinical Laboratory Improvement Amendments (CLIA) program, which sets federal quality standards for human laboratory testing in the United States. There is no official CMS crosswalk between CLIA and NPI numbers; these certificates are associated with this NPI by matching facility names, locations and phone numbers in the CMS CLIA registry.

Certificate of Compliance 05D0550324

Westside Internal Medicine Laboratory · Santa Monica, CA
Active · expires Sep 13, 2027
CLIA Number05D0550324
Laboratory TypePhysician Office
Certificate Effective DateSeptember 14, 2025
Certificate Expiration DateSeptember 13, 2027
Laboratory DirectorJohn Andrews
Laboratory Phone(310) 264-0762
Laboratory LocationWestside Internal Medicine Laboratory2121 Wilshire Blvd, 3rd Fl Lab, Santa Monica, CA 90403
CLIA data matches this NPI record on: Address Name
This certificate is issued to a laboratory after an inspection that finds the laboratory to be in compliance with all applicable CLIA requirements.

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Westside Internal Medicine's NPI number?

The NPI number for Westside Internal Medicine is 1184631251. It was assigned to this organization in the NPPES registry on August 2, 2006.

Where is Westside Internal Medicine located?

Westside Internal Medicine is located at 2121 Wilshire Blvd # 304, Santa Monica, CA 90403. The listed phone number is (310) 264-0065.

What is Westside Internal Medicine's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Westside Internal Medicine enrolled in Medicare?

Yes. Westside Internal Medicine is registered in the Medicare PECOS enrollment system.

How many clinicians bill Medicare through Westside Internal Medicine?

According to the CMS Revalidation Reassignment List (October 2026 release), 9 clinicians in 2 Medicare specialties reassign their Medicare billing to Westside Internal Medicine. A reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for the clinician's services. The largest specialties are Internal Medicine (7) and Family Practice (2). Of these, 9 practice at this address. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Does Westside Internal Medicine hold a CLIA laboratory certificate?

Yes. A Certificate of Compliance (number 05D0550324) is associated with this NPI, valid through September 13, 2027. CLIA certificates authorize laboratory testing under the federal Clinical Laboratory Improvement Amendments program.

When was this NPI record last updated?

The NPPES record for Westside Internal Medicine was last updated on November 26, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 10 months ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.