Mark Thanassi, MD
Emergency Medicine Physician · Santa Clara, CA
Mark Thanassi, MD is an emergency medicine physician with a practice address in Santa Clara, California, and NPI 1104903038, issued on Oct 31, 2006. Check the license (California G86578, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Mark Thanassi
- Credential
- MD
- Primary taxonomy
- Emergency Medicine Physician 207P00000X
- License number
- G86578 CA
Self-reported in NPPES; status is on the state search - Practice location
- 900 Kiely Blvd, Santa Clara, CA 95051
- Phone
- (408) 236-6400
- Enumerated
- Oct 31, 2006
- Record last updated
- Dec 17, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicaid ID
- 00G865780 CA
- Entity
- Type 1 · individual
8 nearest emergency medicine physician records → All 7,751 in California → Look up another NPI →
Also registered at 900 Kiely Blvd
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- James Baxter, MDHospitalist Physician1679659502
- John Budis, RPHPharmacist1104906916
Verify Mark Thanassi in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G86578Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
6% fewer Medicare Part D claims than the average emergency medicine physician in 2024
212 Medicare Part D claims for 131 beneficiaries, against an average of 226 among the 54,106 providers of this specialty who prescribed in Part D.
Most prescribed
- Prednisone21 claims
- Alvesco17 claims
- Naproxen17 claims
- Albuterol Sulfate Hfa16 claims
- Ondansetron Odt14 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.
Mark Thanassi among 7,751 emergency medicine physician records in California
Mark Thanassi, MD is one of 7,751 emergency 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 2006, is newer than 4% of them.
- NPI issued2006 · 4% of these records are older, 60% newer
- In a Medicare fileYes · 81% of these records are
- In the CMS Doctors and Clinicians fileNo · 59% of these records are
- Record last updated2021 · 59% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207P00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
55 emergency medicine physician records list a practice address in Santa Clara
They are 55 of the 3,436 NPPES records with a practice address in Santa Clara, and 7,751 emergency medicine physician records in California.
All 7,751 in California → Every provider in Santa Clara → Emergency Medicine Physician nationwide →
The 8 emergency medicine physician records with the nearest ZIP codes
- Stephen Emond, MDSanta Clara, CA 950511952488801
- Shahinoor Esmail, MDSanta Clara, CA 950511164509006
- Christina Fong, MDSanta Clara, CA 950511518044452
- Gus Garmel, MDSanta Clara, CA 950511235216177
- Eric Koscove, MDSanta Clara, CA 950511871670737
- Anita Kulkarni, MDSanta Clara, CA 950511982781829
- Albert Kuo, MDSanta Clara, CA 950511578640405
- Haydn Leung, MDSanta Clara, CA 950511386721215
Common questions
What is Mark Thanassi, MD's NPI number?
Mark Thanassi, MD's National Provider Identifier (NPI) is 1104903038, issued on Oct 31, 2006. An NPI identifies a provider in billing; it is not a license.
Where is Mark Thanassi, MD located?
The NPPES record lists a practice address at 900 Kiely Blvd, Santa Clara, CA, 95051. Phone: (408) 236-6400. Providers update this record themselves, so call before visiting.
How can I verify Mark Thanassi, MD's license?
NPPES lists California license number G86578, 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 Mark Thanassi, MD prescribe under Medicare Part D?
In 2024, Mark Thanassi, MD had 212 Medicare Part D claims for 131 beneficiaries; the average among emergency medicine physician prescribers was 226. 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.