NPPES file of Aug 9, 2026

John Kwanghyuk Lee, MD

Internal Medicine Physician · Fullerton, CA

John Kwanghyuk Lee, MD is an internal medicine physician with a practice address in Fullerton, California, and NPI 1598721284, issued on Apr 22, 2006. Check the license (California A66137, 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 2023 and 2024 · method · Verify with CMS →

NPPES recordNPPES file of Aug 9, 2026
1598721284
Name
John Kwanghyuk Lee
Credential
MD
Primary taxonomy
Internal Medicine Physician 207R00000X
License number
A66137 CA
Self-reported in NPPES; status is on the state search
Practice location
400 N. Euclid St, Fullerton, CA 91748
Phone
(626) 964-3326
Enumerated
Apr 22, 2006
Record last updated
Oct 29, 2010 (not updated in 16 years: call before relying on the address or phone)
Fax
(626) 964-3346
Medicare enrollment
Enrolled (PECOS I20040721001742); accepts Medicare assignment
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.
Download card Updates feed

Verify John Kwanghyuk Lee in five checks

  1. 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
  2. 2LicenseActive license and public ordersMedical Board of California
    Search for license A66137
    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.

Is this page about you? You can ask us to correct, restrict or remove it: how.

6.7 times the Medicare Part D claims of the average internal medicine physician in 2024

21,350 Medicare Part D claims for 1,274 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 13% of claims. 55 claims were for opioids.

  1. John Lee21,350
  2. Specialty average3,176

Most prescribed

  1. Atorvastatin Calcium2,745 claims
  2. Losartan Potassium1,372 claims
  3. Amlodipine Besylate1,245 claims
  4. Rosuvastatin Calcium648 claims
  5. Alendronate Sodium527 claims
  6. Metformin Hcl516 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.

The MIPS final score for 2023 (Medicare payment program): 97 of 100

The Merit-based Incentive Payment System score is reported for this clinician. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.

  1. Qualityout of 100 · 30% of the final score100.0
  2. Costout of 100 · 30%73.2
  3. Promoting interoperabilitynot scored (reweighted)
  4. Improvement activities40 of 40 points · 15%100.0

Source: CMS Quality Payment Program, MIPS performance year 2023; category weights for 2023 (qpp.cms.gov).

Industry payments in 2024: $156.27

2 payments; by number, the most common kind was food and beverage; the largest payer was Dexcom, 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. John Lee$156.27
  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.

John Kwanghyuk Lee among 17,696 internal medicine physician records in California

John Kwanghyuk Lee, 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 2006, is newer than 5% of them.

  • NPI issued2006 · 5% of these records are older, 56% newer
  • In a Medicare fileYes · 79% of these records are
  • In the CMS Doctors and Clinicians fileYes · 63% of these records are
  • Graduated1990 · median 2004 among the 11,065 with a school on file
  • Record last updated2010 · 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.

The 8 internal medicine physician records with the nearest ZIP codes

  1. Wei Bao, M.D.City Of Industry, CA 917481437199304
  2. Kuo Hsien Chang, MDRowland Heights, CA 917481851392922
  3. Yongqing Feng, M.D.Rowland Heights, CA 917481497806988
  4. Zune Liu, MDRowland Heights, CA 917481619069838
  5. Jason Paek, M.D.Rowland Heights, CA 917481770679631
  6. Rosel Liza Reyes, M.D.Rowland Heights, CA 917481285886978
  7. Chia-Yu Teng, M.D.City Of Industry, CA 917481902839160
  8. Hsiu-Ying Tseng, D.O.Rowland Heights, CA 917481689683831

Common questions

What is John Kwanghyuk Lee, MD's NPI number?

John Kwanghyuk Lee, MD's National Provider Identifier (NPI) is 1598721284, issued on Apr 22, 2006. An NPI identifies a provider in billing; it is not a license.

Where is John Kwanghyuk Lee, MD located?

The NPPES record lists a practice address at 400 N. Euclid St, Fullerton, CA, 91748. Phone: (626) 964-3326. Providers update this record themselves, so call before visiting.

How can I verify John Kwanghyuk Lee, MD's license?

NPPES lists California license number A66137, 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 Kwanghyuk Lee, MD prescribe under Medicare Part D?

In 2024, John Kwanghyuk Lee, MD had 21,350 Medicare Part D claims for 1,274 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.

What is John Kwanghyuk Lee, MD's MIPS final score?

The 2023 MIPS final score is 97 of 100. The average among 454,083 clinicians with a measured score was 83.5.

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.