Katharine Ozeki, M.D.
Gastroenterology Physician · Walnut Creek, CA
Katharine Ozeki, M.D. is a gastroenterology physician with a practice address in Walnut Creek, California, and NPI 1306290838, issued on Apr 21, 2016. Check the license (California A151141, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Katharine Ozeki
- Credential
- M.D.
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- A151141 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1425 S Main St, Walnut Creek, CA 94596
- Phone
- (925) 295-4080
- Enumerated
- Apr 21, 2016
- Record last updated
- Jul 26, 2023
- Medicare enrollment
- Enrolled (PECOS I20190724004057); accepts Medicare assignment
- Medical or professional school
- University Of Southern California Keck School Of Medicine, 2016
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 2,140 in California → Look up another NPI →
Also registered at 1425 S Main St
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Derek Abbassi, MDObstetrics & Gynecology Physician1841364155
- Peter Ackerman, MDEmergency Medicine Physician1427435023
- Aaron Mark Acosta, DOEmergency Medicine Physician1538789987
- Basil Adad, MDOtolaryngology Physician1487732574
- Derek Ailes, M.D.Emergency Medical Services (Emergency Medicine) Physician1992001804
Verify Katharine Ozeki in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A151141Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
42% fewer Medicare Part D claims than the average gastroenterology physician in 2024
467 Medicare Part D claims for 239 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 15% of claims.
Most prescribed
- Omeprazole106 claims
- Gavilyte-C100 claims
- Pantoprazole Sodium33 claims
- Cholestyramine26 claims
- Lubiprostone17 claims
- Metronidazole17 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 IncWalnut Creek, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Katharine Ozeki among 2,140 gastroenterology physician records in California
Katharine Ozeki, M.D. is one of 2,140 gastroenterology physician records with a practice address in California. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2016, is newer than 88% of them.
- NPI issued2016 · 88% of these records are older, 9% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated2016 · median 2002 among the 1,538 with a school on file
- Record last updated2023 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in California
There are 2,140 gastroenterology physician records in California.
All 2,140 in California → Every provider in Walnut Creek → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Eugene Chan, MDWalnut Creek, CA 945961528146610
- Suyi Chang, MDWalnut Creek, CA 945961972681468
- Daniel Chung, MDWalnut Creek, CA 945961063590552
- Ming Fang, MDWalnut Creek, CA 945961366520199
- Steven Fredman, MDWalnut Creek, CA 945961861570962
- Theodore Levin, MDWalnut Creek, CA 945961720166820
- Oliver Lin, M.D.Walnut Creek, CA 945961497981575
- Martha Turchyn-Mazuryk, MDWalnut Creek, CA 945961497821979
Common questions
What is Katharine Ozeki, M.D.'s NPI number?
Katharine Ozeki, M.D.'s National Provider Identifier (NPI) is 1306290838, issued on Apr 21, 2016. An NPI identifies a provider in billing; it is not a license.
Where is Katharine Ozeki, M.D. located?
The NPPES record lists a practice address at 1425 S Main St, Walnut Creek, CA, 94596. Phone: (925) 295-4080. Providers update this record themselves, so call before visiting.
How can I verify Katharine Ozeki, M.D.'s license?
NPPES lists California license number A151141, 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 Katharine Ozeki, M.D. prescribe under Medicare Part D?
In 2024, Katharine Ozeki, M.D. had 467 Medicare Part D claims for 239 beneficiaries; the average among gastroenterology physician prescribers was 811. 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.