NPPES file of Aug 9, 2026

Jonathan Nguyen, M.D.

Internal Medicine Physician · Walnut Creek, CA

Jonathan Nguyen, M.D. is an internal medicine physician with a practice address in Walnut Creek, California, and NPI 1922549138, issued on Mar 20, 2017. Check the license (California A158975, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.

Record from CMS NPPES, file of Aug 9, 2026 · Medicare files 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1922549138
Name
Jonathan Nguyen
Credential
M.D.
Primary taxonomy
Internal Medicine Physician 207R00000X
License number
A158975 CA
Self-reported in NPPES; status is on the state search
Practice location
1515 Newell Ave, Walnut Creek, CA 94596
Phone
(925) 295-4000
Enumerated
Mar 20, 2017
Record last updated
Sep 6, 2022
Medicare enrollment
Enrolled (PECOS I20201214001645); accepts Medicare assignment
Medical or professional school
Drexel University College Of Medicine, 2017
Telehealth
Offers telehealth (CMS)
Entity
Type 1 · individual
Public record from CMS NPPES (open it on the CMS NPI Registry). Enrollment, assignment, school and telehealth: CMS Doctors and Clinicians file, Aug 2026. A record is not a license: verify it with the state board.
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Also registered at 1515 Newell Ave

A shared address usually means a shared clinic or building; it does not show who employs whom.

  1. Natalie Chang, D.O.Internal Medicine Physician1205018561
  2. Whitney Dewalt, M.D.Obstetrics & Gynecology Physician1720382286
  3. Hannelore Harwood, NPWomen's Health Nurse Practitioner1063599272
  4. Andrew Lin, M.D.Nephrology Physician1558484857
  5. Serena LinObstetrics & Gynecology Physician1366650889
  6. Geraldine Shirzai, MDGynecology Physician1609404284

Verify Jonathan Nguyen in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license A158975
    Check the board
  3. 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
  4. 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
  5. 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Open the California license search

PlainDoctor does not match the HHS-OIG exclusion list to individual records: most entries carry no NPI. Search the OIG exclusion list by name.

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24% more Medicare Part D claims than the average internal medicine physician in 2024

3,949 Medicare Part D claims for 1,013 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 9% of claims. 102 claims were for opioids.

  1. Jonathan Nguyen3,949
  2. Specialty average3,176

Most prescribed

  1. Atorvastatin Calcium384 claims
  2. Amlodipine Besylate192 claims
  3. Losartan Potassium143 claims
  4. Levothyroxine Sodium139 claims
  5. Lisinopril128 claims
  6. Atenolol95 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: $22.18

1 payment: food and beverage; the largest payer was Insmed, Inc. 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.

  1. Jonathan Nguyen$22.18
  2. Specialty average$1,303.06

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

  1. Permanente Medical Group IncWalnut Creek, CA

Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).

Jonathan Nguyen among 17,696 internal medicine physician records in California

Jonathan Nguyen, 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 2017, is newer than 81% of them.

  • NPI issued2017 · 81% of these records are older, 16% newer
  • In a Medicare fileYes · 79% of these records are
  • In the CMS Doctors and Clinicians fileYes · 63% of these records are
  • Graduated2017 · median 2004 among the 11,065 with a school on file
  • Record last updated2022 · 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).

183 internal medicine physician records list a practice address in Walnut Creek

They are 183 of the 6,170 NPPES records with a practice address in Walnut Creek, and 17,696 internal medicine physician records in California.

The 8 internal medicine physician records with the nearest ZIP codes

  1. Anthony Arroyo, MDWalnut Creek, CA 945961376621458
  2. Sheila Bhatia, MDWalnut Creek, CA 945961225135379
  3. Amrita Dhaliwal, MDWalnut Creek, CA 945961164500740
  4. Nellia Karakozova, MDWalnut Creek, CA 945961659459154
  5. Joseph Long, MDWalnut Creek, CA 945961225116379
  6. Roxanne McDaniel, MDWalnut Creek, CA 945961457439937
  7. Huu Nguyen, D.O.Walnut Creek, CA 945961811966492
  8. Jeff Ortiz, MDWalnut Creek, CA 945961891873964

Common questions

What is Jonathan Nguyen, M.D.'s NPI number?

Jonathan Nguyen, M.D.'s National Provider Identifier (NPI) is 1922549138, issued on Mar 20, 2017. An NPI identifies a provider in billing; it is not a license.

Where is Jonathan Nguyen, M.D. located?

The NPPES record lists a practice address at 1515 Newell Ave, Walnut Creek, CA, 94596. Phone: (925) 295-4000. Providers update this record themselves, so call before visiting.

How can I verify Jonathan Nguyen, M.D.'s license?

NPPES lists California license number A158975, 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 Jonathan Nguyen, M.D. prescribe under Medicare Part D?

In 2024, Jonathan Nguyen, M.D. had 3,949 Medicare Part D claims for 1,013 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.