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Internal Medicine Providers in Fullerton, CA

Browse 44 Internal Medicine providers listed in NPPES with a practice address in Fullerton, California.

44 Healthcare Providers

How Fullerton compares with the U.S.

Fullerton has 31 clinicians in Internal Medicine per 100,000 residents, about 70% of the U.S. rate of 44.

That is 44 active clinicians in Internal Medicine with a practice address in Fullerton, for a population of 140,968.

The California rate is 45 per 100,000 residents.

What these numbers mean

Clinicians per 100,000 residents compares places of different sizes. We count active clinicians who list a practice address in the area in the federal NPI registry (NPPES) and divide by the number of people who live there, according to the U.S. Census Bureau. The U.S. rate is the same calculation for the whole country.

A higher number does not mean it is easier to get an appointment, that wait times are shorter, or that care is better. It also does not show how many clinicians are accepting new patients or which insurance plans they take. A lower number does not by itself mean there is a shortage.

City counts use the city name in each clinician's practice address. That postal city can cover a larger or smaller area than the city limits the Census Bureau uses for population, and many clinicians list only one address even if they work in several places.

100% of clinicians in Internal Medicine in Fullerton listed in the CMS Medicare file (37 of 37) accept Medicare assignment. That is similar to the California share of 96%.

What is Medicare assignment?

A clinician who accepts Medicare assignment agrees to take the Medicare-approved amount as full payment for services that Original Medicare covers. You usually still pay your deductible and coinsurance. This comes from the CMS Doctors and Clinicians file and applies to Original Medicare only. Medicare Advantage plans have their own provider networks. It does not show whether a clinician is taking new patients.

Some clinicians are listed as "may accept assignment," which means they can decide case by case. Clinicians without an assignment flag, or who are not in the CMS file, are not counted as accepting assignment. That does not mean they refuse Medicare. Ask the office before your visit.

32% of clinicians in Internal Medicine in Fullerton listed in the CMS Medicare file (12 of 37) have a CMS telehealth indicator, meaning their recent Medicare claims include telehealth services. That is lower than the California share of 38%.

About the telehealth indicator

The telehealth indicator comes from CMS. It marks clinicians whose recent paid Medicare claims include services delivered by telehealth. It means a clinician has provided some services by telehealth, not that every visit can be done online. A clinician without the indicator may still offer telehealth, for example to patients who are not on Medicare. Ask the office which visits can be done by video or phone.

These figures summarize public federal data. They do not measure quality of care, appointment availability, or whether a clinician accepts your insurance or new patients. Registry addresses can be out of date. Please confirm details directly with the office and your plan. This information is not medical advice.

Prepared by T-MedInfo from NPPES, CMS and U.S. Census Bureau data. Questions or corrections: support@true-medinfo.com ยท Methodology

Sources: Clinician counts and practice addresses: NPPES NPI Registry, Centers for Medicare & Medicaid Services (CMS), data as of August 2026. Medicare assignment and telehealth indicators: CMS Doctors and Clinicians National Downloadable File. Population: U.S. Census Bureau, American Community Survey 2020-2024 5-Year Estimates, Table B01003 (Total Population).

Internal Medicine Medicare (PECOS) Enrollment & Ordering Eligibility

Medicare enrollment and order/referring eligibility listed by CMS for Internal Medicine practitioners in Fullerton, CA

Source: CMS PECOS
PECOS Enrolled Specialists 40 In Fullerton, CA
Part B Lab & Imaging Eligible 40 Diagnostic Referrals
DME Ordering Eligible 40 Durable Medical Equipment
Home Health Agency Referrals 40 HHA Ordering Eligible
Showing 1โ€“20 of 44 providers
With recent CMS data first, then Aโ€“Z

Dr. Sang Hoon Ahn , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
1950 Sunny Crest Dr Ste 2800, Fullerton, CA 928353641
Phone: 6578889919
NPI Identifier 1568581759
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Dr. Amy Alias , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
2141 N Harbor Blvd Ste 25000, Fullerton, CA 928353830
Phone: 7146268615
NPI Identifier 1306015607
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Dr. Rajiv I Bhavsar , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
1321 N Harbor Blvd, Suite # 302, Fullerton, CA 928354124
Phone: 7144410591
NPI Identifier 1477550648
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Dr. Bradley Borsari , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
2141 N Harbor Blvd, Suite 25000, Fullerton, CA 928353827
Phone: 7146268610
NPI Identifier 1104826619
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Dr. Panagiotis P Bougas , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
220 Laguna Rd, Suite 2, Fullerton, CA 928352523
Phone: 7144467454
NPI Identifier 1295814275
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Dr. Ruben Cabral , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
2141 N Harbor Blvd, Suite 25000, Fullerton, CA 928353827
Phone: 7146268610
NPI Identifier 1568458008
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Dr. Sammie Tran Cheng , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
101 E Valencia Mesa Dr, Fullerton, CA 928353809
Phone: 7147059877
NPI Identifier 1306118666
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Dr. Sara Choi , DO

Internal Medicine

Active NPI Status Accepts Medicare Assignment
101 E Valencia Mesa Dr, Fullerton, CA 928353809
Phone: 7149923969
NPI Identifier 1346876349
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Dr. Anthony Crymes , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
101 E Valencia Mesa Dr Ste 311, Fullerton, CA 928353809
Phone: 7144475027
NPI Identifier 1639829625
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Dr. Arash Farahanchi , DO

Internal Medicine

Active NPI Status Accepts Medicare Assignment
2251 N Harbor Blvd, Fullerton, CA 928352601
Phone: 7144496230
NPI Identifier 1497829972
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Dr. Leo Garcia , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
2141 N Harbor Blvd, Suite 25000, Fullerton, CA 928353827
Phone: 7146268610
NPI Identifier 1831185792
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Dr. Kristopher A Huston , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
101 E Valencia Mesa Dr, Fullerton, CA 928353809
Phone: 7148713280
NPI Identifier 1831517390
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Dr. Michael A Katz , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
101 E Valencia Mesa Dr, Fullerton, CA 928353809
Phone: 7149923969
NPI Identifier 1841213899
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Dr. Eleanor Marie Kelly , MD

Internal Medicine

Active NPI Status
241 Imperial Hwy, Suite 350, Fullerton, CA 928351055
Phone: 7145788669
NPI Identifier 1912080094
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Dr. Jae K Kim , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
100 E Valencia Mesa Dr Ste 311, Fullerton, CA 928353800
Phone: 7144465590
NPI Identifier 1083642839
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Dr. Pius J. Kim , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
101 E Valencia Mesa Dr, Fullerton, CA 928353809
Phone: 7144475027
NPI Identifier 1003863317
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Dr. Linda Lam , MD

Internal Medicine

Active NPI Status
101 E Valencia Mesa Dr, Fullerton, CA 92835
Phone: 7148713280
NPI Identifier 1639180086
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Dr. John Kwanghyuk Lee , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment Telehealth Services Available
400 N. Euclid St, Fullerton, CA 917481625
Phone: 6269643326
NPI Identifier 1598721284
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Dr. Alex Leung , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
279 Imperial Hwy, Suite 730, Fullerton, CA 928351041
Phone: 7144494842
NPI Identifier 1669414512
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Dr. Yang Li , MD

Internal Medicine

Active NPI Status Accepts Medicare Assignment
101 E Valencia Mesa Dr, Fullerton, CA 92835
Phone: 7149923257
NPI Identifier 1396035564
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Frequently Asked Questions about Internal Medicine in Fullerton

How do I check a Internal Medicine practitioner's license?

Each practitioner profile shows the NUCC taxonomy code and any state license number the practitioner reported to NPPES, plus a link to the California licensing board lookup. NPPES entries are self-reported; current license status is published only by the state board.

Why is a practitioner missing from this list?

This list shows NPI records that are active in NPPES. A deactivated NPI keeps its profile with the deactivation date and practice history; find it with the site search by name or NPI number.