Thomas S. Lam, M.D.
Gastroenterology Physician · Alhambra, CA
Thomas S. Lam, M.D. is a gastroenterology physician with a practice address in Alhambra, California, and NPI 1437185295, issued on Jun 24, 2006. Check the license (California A44280, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Thomas S. Lam
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- A44280 CA
Self-reported in NPPES; status is on the state search - Practice location
- 333 S Garfield Ave Ste A, Alhambra, CA 91801
- Phone
- (626) 284-1997
- Enumerated
- Jun 24, 2006
- Record last updated
- Jun 17, 2025
- Fax
- (626) 284-2549
- Medicaid IDs
- 00A442800 CA
00A442801 CA - Medicare enrollment
- Enrolled (PECOS I20040727001651); accepts Medicare assignment
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 2,140 in California → Look up another NPI →
Also registered at 333 S Garfield Ave Ste A
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Sunny Wong, MDGastroenterology Physician1972669919
- Tianyuan Yang, NPFamily Nurse Practitioner1831058205
Verify Thomas S. Lam in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A44280Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
31% fewer Medicare Part D claims than the average gastroenterology physician in 2024
562 Medicare Part D claims for 367 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 3% of claims.
Most prescribed
- Gavilyte-G287 claims
- Omeprazole58 claims
- Gavilyte-C33 claims
- Warfarin Sodium27 claims
- Famotidine24 claims
- Pantoprazole Sodium18 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.
Bills Medicare through one group practice
- Amg A Professional Medical CorporationAlhambra, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Thomas S. Lam among 2,140 gastroenterology physician records in California
Thomas S. Lam, M.D. is one of 2,140 gastroenterology physician records with a practice address in California. 83% 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 7% of them.
- NPI issued2006 · 7% of these records are older, 48% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated1981 · median 2002 among the 1,538 with a school on file
- Record last updated2025 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in California
There are 2,140 gastroenterology physician records in California.
All 2,140 in California → Every provider in Alhambra → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Ashraf Ashhab, MDAlhambra, CA 918011235581604
- Sunny Wong, MDAlhambra, CA 918011972669919
- Kelvin Yeh, M.D.Alhambra, CA 918011104063940
- Mumtaz Akram, M.D.West Covina, CA 917901144325242
- Sartaj Arora, MDWest Covina, CA 917901841258340
- Osama Sidhom, MDWest Corina, CA 917901649238148
- Patrick Truong, M.D.West Covina, CA 917901326237819
- Basim Abdelkarim, MDUpland, CA 917861932217544
Common questions
What is Thomas S. Lam, M.D.'s NPI number?
Thomas S. Lam, M.D.'s National Provider Identifier (NPI) is 1437185295, issued on Jun 24, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Thomas S. Lam, M.D. located?
The NPPES record lists a practice address at 333 S Garfield Ave Ste A, Alhambra, CA, 91801. Phone: (626) 284-1997. Providers update this record themselves, so call before visiting.
How can I verify Thomas S. Lam, M.D.'s license?
NPPES lists California license number A44280, 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 Thomas S. Lam, M.D. prescribe under Medicare Part D?
In 2024, Thomas S. Lam, M.D. had 562 Medicare Part D claims for 367 beneficiaries; the average among gastroenterology physician prescribers was 811. 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.