Justin Tam Siu, MD
Family Medicine Physician · Los Angeles, CA
Justin Tam Siu, MD is a family medicine physician with a practice address in Los Angeles, California, and NPI 1407542467, issued on Apr 13, 2023. Check the license (California A198786, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Justin Tam Siu
- Credential
- MD
- Primary taxonomy
- Family Medicine Physician 207Q00000X
- License number
- A198786 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1520 San Pablo St Ste 1300, Los Angeles, CA 90033
- Phone
- (323) 442-5900
- Enumerated
- Apr 13, 2023
- Record last updated
- Jul 9, 2026
- Medicare enrollment
- Enrolled (PECOS I20260605003865); may accept Medicare assignment
- Entity
- Type 1 · individual
8 nearest family medicine physician records → All 17,133 in California → Look up another NPI →
Also registered at 1520 San Pablo St Ste 1300
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Justin Tam Siu in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A198786Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
93% fewer Medicare Part D claims than the average family medicine physician in 2024
244 Medicare Part D claims for 40 beneficiaries, against an average of 3,544 among the 117,163 providers of this specialty who prescribed in Part D.
Most prescribed
- Prednisone19 claims
- Amlodipine Besylate18 claims
- Azithromycin18 claims
- Atorvastatin Calcium13 claims
- Levothyroxine Sodium11 claims
- Losartan Potassium11 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.
Justin Tam Siu among 17,133 family medicine physician records in California
Justin Tam Siu, MD is one of 17,133 family medicine physician records with a practice address in California. 81% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2023, is newer than 97% of them.
- NPI issued2023 · 97% of these records are older, 1% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileYes · 62% of these records are
- Graduated2023 · median 2005 among the 10,652 with a school on file
- Record last updated2026 · 58% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207Q00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
829 family medicine physician records list a practice address in Los Angeles
They are 829 of the 69,537 NPPES records with a practice address in Los Angeles, and 17,133 family medicine physician records in California.
All 17,133 in California → Every provider in Los Angeles → Family Medicine Physician nationwide →
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Common questions
What is Justin Tam Siu, MD's NPI number?
Justin Tam Siu, MD's National Provider Identifier (NPI) is 1407542467, issued on Apr 13, 2023. An NPI identifies a provider in billing; it is not a license.
Where is Justin Tam Siu, MD located?
The NPPES record lists a practice address at 1520 San Pablo St Ste 1300, Los Angeles, CA, 90033. Phone: (323) 442-5900. Providers update this record themselves, so call before visiting.
How can I verify Justin Tam Siu, MD's license?
NPPES lists California license number A198786, 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 Justin Tam Siu, MD prescribe under Medicare Part D?
In 2024, Justin Tam Siu, MD had 244 Medicare Part D claims for 40 beneficiaries; the average among family medicine physician prescribers was 3,544. 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.