Thiri T. Oo, M.D.
Internal Medicine Physician · Claremont, CA
Thiri T. Oo, M.D. is an internal medicine physician with a practice address in Claremont, California, and NPI 1619256617, issued on Aug 8, 2011. Check the license (California A117718, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Thiri T. Oo
- Credential
- M.D.
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- A117718 CA
Self-reported in NPPES; status is on the state search - Practice location
- 250 W San Jose Ave, Claremont, CA 91711
- Phone
- (833) 574-2273
- Enumerated
- Aug 8, 2011
- Record last updated
- Dec 1, 2021 (not updated in 5 years: call before relying on the address or phone)
- Medicare enrollment
- Enrolled (PECOS I20130418000493); 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 250 W San Jose Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Jin Park, D.O.Family Medicine Physician1992800353
- Jonathan Siu, D.O.Family Medicine Physician1346652179
Verify Thiri T. Oo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A117718Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.2 times the Medicare Part D claims of the average internal medicine physician in 2024
6,969 Medicare Part D claims for 612 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 7% of claims. 354 claims were for opioids.
Most prescribed
- Atorvastatin Calcium488 claims
- Amlodipine Besylate275 claims
- Losartan Potassium271 claims
- Lisinopril264 claims
- Levothyroxine Sodium254 claims
- Hydrocodone-Acetaminophen183 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
- Southern California Permanente Medical GroupClaremont, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Thiri T. Oo among 17,696 internal medicine physician records in California
Thiri T. Oo, M.D. 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 2011, is newer than 66% of them.
- NPI issued2011 · 66% of these records are older, 32% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2009 · median 2004 among the 11,065 with a school on file
- Record last updated2021 · 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).
Internal Medicine Physician providers in California
There are 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Claremont → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Ashok Sharma, MDClaremont, CA 917111205804580
- Howard Chen, DOChino, CA 917101699968339
- Jonathan Cho, M.D.Chino, CA 917101235175936
- Robert Clinton, M.D.Chino, CA 917101265566699
- Ali Etemadian, D.O.Chino, CA 917101316041718
- Mao-Jin Fu, M.D.Chino, CA 917101568680395
- Gerardo General, MDChino, CA 917101649295635
- Tuan Hoang, MDChino, CA 917101013122761
Common questions
What is Thiri T. Oo, M.D.'s NPI number?
Thiri T. Oo, M.D.'s National Provider Identifier (NPI) is 1619256617, issued on Aug 8, 2011. An NPI identifies a provider in billing; it is not a license.
Where is Thiri T. Oo, M.D. located?
The NPPES record lists a practice address at 250 W San Jose Ave, Claremont, CA, 91711. Phone: (833) 574-2273. Providers update this record themselves, so call before visiting.
How can I verify Thiri T. Oo, M.D.'s license?
NPPES lists California license number A117718, 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 Thiri T. Oo, M.D. prescribe under Medicare Part D?
In 2024, Thiri T. Oo, M.D. had 6,969 Medicare Part D claims for 612 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.