Sang Hoon Ahn, M.D.
Internal Medicine Physician · Fullerton, CA
Sang Hoon Ahn, M.D. is an internal medicine physician with a practice address in Fullerton, California, and NPI 1568581759, issued on Mar 28, 2007. Check the license (California A95562, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Sang Hoon Ahn
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A95562 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1950 Sunny Crest Dr Ste 2800, Fullerton, CA 92835
- Phone
- (657) 888-9919
- Enumerated
- Mar 28, 2007
- Record last updated
- Feb 18, 2026
- Fax
- (657) 888-9941
- Medicaid ID
- 00A955620 CA
- Medicare enrollment
- Enrolled (PECOS I20080917000657); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 1950 Sunny Crest Dr Ste 2800
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Jane Kim, PA-CPhysician Assistant1881320638
Verify Sang Hoon Ahn in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A95562Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
60% fewer Medicare Part D claims than the average internal medicine physician in 2024
1,278 Medicare Part D claims for 213 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 21 claims were for opioids.
Most prescribed
- Anastrozole83 claims
- Letrozole83 claims
- Promacta78 claims
- Tagrisso75 claims
- Abiraterone Acetate53 claims
- Erleada53 claims
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Industry payments in 2024: $48.36
3 payments; by number, the most common kind was education; the largest payer was Merck Sharp & Dohme LLC. The 50,334 providers of this specialty with any payment received $1,303.06 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- Usc Care Medical Group IncLos Angeles, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Sang Hoon Ahn among 17,696 internal medicine physician records in California
Sang Hoon Ahn, M.D. is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 44% of them.
- NPI issued2007 · 44% of these records are older, 44% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated1994 · median 2004 among the 11,065 with a school on file
- Record last updated2026 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
44 internal medicine physician records list a practice address in Fullerton
They are 44 of the 5,437 NPPES records with a practice address in Fullerton, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Fullerton → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Rajiv Bhavsar, M.D.Fullerton, CA 928351477550648
- Bradley Borsari, MDFullerton, CA 928351104826619
- Eugene BostonFullerton, CA 928351023019965
- Ruben Cabral, MDFullerton, CA 928351568458008
- Friedhelm Cordes, M.D.Fullerton, CA 928351588650931
- Robert Francis, M.D.Fullerton, CA 928351366439804
- Leo Garcia, M.D.Fullerton, CA 928351831185792
- Pius Kim, M.D.Fullerton, CA 928351003863317
Common questions
What is Sang Hoon Ahn, M.D.'s NPI number?
Sang Hoon Ahn, M.D.'s National Provider Identifier (NPI) is 1568581759, issued on Mar 28, 2007. An NPI identifies a provider in billing; it is not a license.
Where is Sang Hoon Ahn, M.D. located?
The NPPES record lists a practice address at 1950 Sunny Crest Dr Ste 2800, Fullerton, CA, 92835. Phone: (657) 888-9919. Providers update this record themselves, so call before visiting.
How can I verify Sang Hoon Ahn, M.D.'s license?
NPPES lists California license number A95562, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Sang Hoon Ahn, M.D. prescribe under Medicare Part D?
In 2024, Sang Hoon Ahn, M.D. had 1,278 Medicare Part D claims for 213 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.