Tatiana Tam, DO
Internal Medicine Physician · Vallejo, CA
Tatiana Tam, DO is an internal medicine physician with a practice address in Vallejo, California, and NPI 1790304988, issued on Apr 8, 2020. Check the license (California 20A21019, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Tatiana Tam
- Credential
- DO
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 20A21019 CA
Self-reported in NPPES; status is on the state search - Practice location
- 975 Sereno Dr, Vallejo, CA 94589
- Phone
- (707) 651-1000
- Enumerated
- Apr 8, 2020
- Record last updated
- Aug 31, 2023
- Medicare enrollment
- Enrolled (PECOS I20231006001799); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 975 Sereno Dr
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Joel Aandahl, NPAdult Health Nurse Practitioner1891423653
- Noman Absar, MDCritical Care Medicine (Internal Medicine) Physician1205908951
- Anthony Acquaviva, MDUrology Physician1457439283
- Jhonnard James Acuna, CRNACertified Registered Nurse Anesthetist1205997327
- Omid AfshariPharmacist1184165391
- Eesha AftabStudent in an Organized Health Care Education/Training Program1770421687
Verify Tatiana Tam in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A21019Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
87% fewer Medicare Part D claims than the average internal medicine physician in 2024
428 Medicare Part D claims for 151 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. 11 claims were for opioids.
Most prescribed
- Furosemide33 claims
- Atorvastatin Calcium21 claims
- Doxycycline Monohydrate21 claims
- Amoxicillin-Clavulanate Potass20 claims
- Amlodipine Besylate18 claims
- Metoprolol Succinate18 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 IncVallejo, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Tatiana Tam among 17,696 internal medicine physician records in California
Tatiana Tam, DO 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 2020, is newer than 89% of them.
- NPI issued2020 · 89% of these records are older, 8% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2020 · median 2004 among the 11,065 with a school on file
- Record last updated2023 · 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).
64 internal medicine physician records list a practice address in Vallejo
They are 64 of the 2,836 NPPES records with a practice address in Vallejo, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Vallejo → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Robert Anderson, M.D.Vallejo, CA 945891265454623
- Richard Chesley, MDVallejo, CA 945891760560585
- Jonathan Kaner, MDVallejo, CA 945891457439358
- Kelvin Kay, M.D.Vallejo, CA 945891588778542
- Aye Kyu, MDVallejo, CA 945891255430005
- Becky Lee, MDVallejo, CA 945891487732376
- Scarlet McClure, MDVallejo, CA 945891033176979
- Lechi Pham, MDVallejo, CA 945891467530287
Common questions
What is Tatiana Tam, DO's NPI number?
Tatiana Tam, DO's National Provider Identifier (NPI) is 1790304988, issued on Apr 8, 2020. An NPI identifies a provider in billing; it is not a license.
Where is Tatiana Tam, DO located?
The NPPES record lists a practice address at 975 Sereno Dr, Vallejo, CA, 94589. Phone: (707) 651-1000. Providers update this record themselves, so call before visiting.
How can I verify Tatiana Tam, DO's license?
NPPES lists California license number 20A21019, 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 Tatiana Tam, DO prescribe under Medicare Part D?
In 2024, Tatiana Tam, DO had 428 Medicare Part D claims for 151 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.