Williamson Le
Internal Medicine Physician · San Rafael, CA
Williamson Le is an internal medicine physician with a practice address in San Rafael, California, and NPI 1487231247, issued on Mar 26, 2021. Check the license (California A193437, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Williamson Le
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License numbers
- A193437 CA
TLL-2023-007 GU
Self-reported in NPPES; status is on the state search - Practice location
- 99 Montecillo RD, San Rafael, CA 94903
- Phone
- (415) 444-2000
- Enumerated
- Mar 26, 2021
- Record last updated
- Jul 3, 2024
- Medicare enrollment
- Enrolled (PECOS I20240725003912); accepts Medicare assignment
- Medical or professional school
- Loma Linda University School Of Medicine, 2021
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 99 Montecillo RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Williamson Le in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A193437Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
72% fewer Medicare Part D claims than the average internal medicine physician in 2024
888 Medicare Part D claims for 228 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Most prescribed
- Atorvastatin Calcium79 claims
- Amlodipine Besylate49 claims
- Lisinopril39 claims
- Metoprolol Tartrate35 claims
- Gabapentin33 claims
- Losartan Potassium29 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
- Permanente Medical Group IncFremont, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Williamson Le among 17,696 internal medicine physician records in California
Williamson Le 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 2021, is newer than 92% of them.
- NPI issued2021 · 92% of these records are older, 5% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2021 · median 2004 among the 11,065 with a school on file
- Record last updated2024 · 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).
51 internal medicine physician records list a practice address in San Rafael
They are 51 of the 3,159 NPPES records with a practice address in San Rafael, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in San Rafael → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
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- Bryn Duffy, MDSan Rafael, CA 949031235243775
- Jill Dunton, MDSan Rafael, CA 949031588748552
- Joseph Habis, M.D.San Rafael, CA 949031760439681
- Jeffrey Harris, MDSan Rafael, CA 949031134203136
- Alpana Kharkar, MDSan Rafael, CA 949031982788055
- Steven Killpack, MDSan Rafael, CA 949031477651149
- Alan Kneitel, MDSan Rafael, CA 949031417031584
Common questions
What is Williamson Le's NPI number?
Williamson Le's National Provider Identifier (NPI) is 1487231247, issued on Mar 26, 2021. An NPI identifies a provider in billing; it is not a license.
Where is Williamson Le located?
The NPPES record lists a practice address at 99 Montecillo RD, San Rafael, CA, 94903. Phone: (415) 444-2000. Providers update this record themselves, so call before visiting.
How can I verify Williamson Le's license?
NPPES lists California license number A193437, 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 Williamson Le prescribe under Medicare Part D?
In 2024, Williamson Le had 888 Medicare Part D claims for 228 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.