John Feng, MD
Internal Medicine Physician · Santa Ana, CA
John Feng, MD is an internal medicine physician with a practice address in Santa Ana, California, and NPI 1346660081, issued on Apr 21, 2014. Check the license (California A139812, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- John Feng
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A139812 CA
Self-reported in NPPES; status is on the state search - Practice location
- 3401 W Sunflower Ave Ste 100, Santa Ana, CA 92704
- Phone
- (888) 789-9585
- Enumerated
- Apr 21, 2014
- Record last updated
- Oct 9, 2019 (not updated in 7 years: call before relying on the address or phone)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Verify John Feng in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A139812Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
57% fewer Medicare Part D claims than the average internal medicine physician in 2024
1,377 Medicare Part D claims for 145 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Atorvastatin Calcium91 claims
- Amlodipine Besylate81 claims
- Eliquis71 claims
- Levothyroxine Sodium57 claims
- Losartan Potassium56 claims
- Potassium Chloride50 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.
John Feng among 17,696 internal medicine physician records in California
John Feng, MD 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 2014, is newer than 74% of them.
- NPI issued2014 · 74% of these records are older, 24% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileNo · 63% of these records are
- Record last updated2019 · 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).
Internal Medicine Physician providers in California
There are 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Santa Ana → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Ronnie Alas, M.D.Santa Ana, CA 927041306267026
- Robert Castro, DOSanta Ana, CA 927041285777813
- Robin Hatam, D.O.Santa Ana, CA 927041194053785
- Iyad Houshan, M.D.Santa Ana, CA 927041497773287
- Wesam Houshan, MDSanta Ana, CA 927041356467112
- Ajay Meka, M.D.Santa Ana, CA 927041063527976
- Meena Meka, M.D.Santa Ana, CA 927041013338722
- Madhavi Mulye, M.D.Santa Ana, CA 927041205056470
Common questions
What is John Feng, MD's NPI number?
John Feng, MD's National Provider Identifier (NPI) is 1346660081, issued on Apr 21, 2014. An NPI identifies a provider in billing; it is not a license.
Where is John Feng, MD located?
The NPPES record lists a practice address at 3401 W Sunflower Ave Ste 100, Santa Ana, CA, 92704. Phone: (888) 789-9585. Providers update this record themselves, so call before visiting.
How can I verify John Feng, MD's license?
NPPES lists California license number A139812, 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 John Feng, MD prescribe under Medicare Part D?
In 2024, John Feng, MD had 1,377 Medicare Part D claims for 145 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.