John Vaughn Siebel, M.D.
Medical Oncology Physician · San Mateo, CA
John Vaughn Siebel, M.D. is a medical oncology physician with a practice address in San Mateo, California, and NPI 1780741306, issued on Jan 2, 2007. Check the license (California G26383, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- John Vaughn Siebel
- Credential
- M.D.
- Primary taxonomy
- Medical Oncology Physician 207RX0202X
- License numbers
- G26383 CA
M-13451 ID
Self-reported in NPPES; status is on the state search - Practice location
- 218 DE Anza Blvd, San Mateo, CA 94402
- Phone
- (650) 341-9131
- Enumerated
- Jan 2, 2007
- Record last updated
- Nov 7, 2018 (not updated in 8 years: call before relying on the address or phone)
- Fax
- (650) 341-9135
- Entity
- Type 1 · individual
8 nearest medical oncology physician records → All 447 in California → Look up another NPI →
Also registered at 218 DE Anza Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Kent Adler, M.D.Hematology & Oncology Physician1013074632
- Jennifer Brown, M.D.Hematology & Oncology Physician1740347350
- Ryan ChangMedical Oncology Physician1164985263
- Karen Chee, M.D.Hematology & Oncology Physician1487637310
- Shu Yi Chen, RPHPharmacist1902401250
- Bradley Ekstrand, M.D., PH.D.Hematology & Oncology Physician1528125135
Verify John Vaughn Siebel in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G26383Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
94% fewer Medicare Part D claims than the average medical oncology physician in 2024
43 Medicare Part D claims, against an average of 703 among the 4,230 providers of this specialty who prescribed in Part D.
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.
John Vaughn Siebel among 447 medical oncology physician records in California
John Vaughn Siebel, M.D. is one of 447 medical oncology physician records with a practice address in California. 82% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2007, is newer than 45% of them.
- NPI issued2007 · 45% of these records are older, 44% newer
- In a Medicare fileYes · 82% of these records are
- In the CMS Doctors and Clinicians fileNo · 70% of these records are
- Record last updated2018 · 41% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RX0202X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Medical Oncology Physician providers in California
There are 447 medical oncology physician records in California.
All 447 in California → Every provider in San Mateo → Medical Oncology Physician nationwide →
The 8 medical oncology physician records with the nearest ZIP codes
- Ryan ChangSan Mateo, CA 944021164985263
- Matthew Lee, D.O.San Mateo, CA 944021326589581
- Casey Bermack, MD PHDFoster City, CA 944041588125199
- Ann Lowe, M.D.Palo Alto, CA 943061013278811
- Pamela Basto, MD, PHDStanford, CA 943051194221903
- James Dickerson, MDStanford, CA 943051851897813
- Timothy Ellis-Caleo, MDStanford, CA 943051891258737
- Jordan Goldstein, MDStanford, CA 943051295231603
Common questions
What is John Vaughn Siebel, M.D.'s NPI number?
John Vaughn Siebel, M.D.'s National Provider Identifier (NPI) is 1780741306, issued on Jan 2, 2007. An NPI identifies a provider in billing; it is not a license.
Where is John Vaughn Siebel, M.D. located?
The NPPES record lists a practice address at 218 DE Anza Blvd, San Mateo, CA, 94402. Phone: (650) 341-9131. Providers update this record themselves, so call before visiting.
How can I verify John Vaughn Siebel, M.D.'s license?
NPPES lists California license number G26383, 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 Vaughn Siebel, M.D. prescribe under Medicare Part D?
In 2024, John Vaughn Siebel, M.D. had 43 Medicare Part D claims; the average among medical oncology physician prescribers was 703. 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.