Mariko Ishiyama, D.O
Hospitalist Physician · Modesto, CA
Mariko Ishiyama, D.O is a hospitalist physician with a practice address in Modesto, California, and NPI 1952662991, issued on Jun 6, 2012. Check the license (California 12904, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Mariko Ishiyama
- Credential
- D.O
- Primary taxonomy
- Hospitalist Physician 208M00000X
- License numbers
- 12904 CA
20A13309 CA
Self-reported in NPPES; status is on the state search - Practice location
- 1441 Florida Ave, Modesto, CA 95350
- Phone
- (209) 576-3525
- Enumerated
- Jun 6, 2012
- Record last updated
- Aug 14, 2024
- Medicare enrollment
- Enrolled (PECOS I20150928000736); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest hospitalist physician records → All 3,099 in California → Look up another NPI →
Also registered at 1441 Florida Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Thadeo Aceves, PA-CPhysician Assistant1821358375
- Arya AfzaliStudent in an Organized Health Care Education/Training Program1841975646
- Sheena Allen, PAMedical Physician Assistant1134473564
- Angel Arellano, PA-CPhysician Assistant1114864634
Verify Mariko Ishiyama in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 12904Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
91% fewer Medicare Part D claims than the average hospitalist physician in 2024
48 Medicare Part D claims for 15 beneficiaries, against an average of 521 among the 21,613 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.
The practice group's MIPS final score for 2023 (Medicare payment program): 85.7 of 100
The Merit-based Incentive Payment System score is reported for the practice group, not for one clinician alone. Four categories are weighted into the final score; the average among 454,083 clinicians with a measured score was 83.5.
Source: CMS Quality Payment Program, MIPS performance year 2023, group reporting; category weights for 2023 (qpp.cms.gov).
Bills Medicare through 2 group practices
- Galen Inpatient Physicians PCVictorville, CA
- John Muir Physician NetworkConcord, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Mariko Ishiyama among 3,099 hospitalist physician records in California
Mariko Ishiyama, D.O is one of 3,099 hospitalist physician records with a practice address in California. 90% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2012, is newer than 51% of them.
- NPI issued2012 · 51% of these records are older, 44% newer
- In a Medicare fileYes · 90% of these records are
- In the CMS Doctors and Clinicians fileYes · 81% of these records are
- Graduated2012 · median 2010 among the 2,505 with a school on file
- Record last updated2024 · 49% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 208M00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Hospitalist Physician providers in California
There are 3,099 hospitalist physician records in California.
All 3,099 in California → Every provider in Modesto → Hospitalist Physician nationwide →
The 8 hospitalist physician records with the nearest ZIP codes
- Julianna Bojta, MDModesto, CA 953501841378908
- Tuhin Chaudhury, M.D.Modesto, CA 953501376779454
- Pankaj Malhotra, MDModesto, CA 953501851561203
- Arun Manoharan, MDModesto, CA 953501730393836
- Kevin Sterling, MDModesto, CA 953501881757409
- Satya Toram, MDModesto, CA 953501225175029
- Christopher Anago, M.D.Modesto, CA 953551578529673
- Sohail Gagan, M.D.Modesto, CA 953551821054594
Common questions
What is Mariko Ishiyama, D.O's NPI number?
Mariko Ishiyama, D.O's National Provider Identifier (NPI) is 1952662991, issued on Jun 6, 2012. An NPI identifies a provider in billing; it is not a license.
Where is Mariko Ishiyama, D.O located?
The NPPES record lists a practice address at 1441 Florida Ave, Modesto, CA, 95350. Phone: (209) 576-3525. Providers update this record themselves, so call before visiting.
How can I verify Mariko Ishiyama, D.O's license?
NPPES lists California license number 12904, 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 Mariko Ishiyama, D.O prescribe under Medicare Part D?
In 2024, Mariko Ishiyama, D.O had 48 Medicare Part D claims for 15 beneficiaries; the average among hospitalist physician prescribers was 521. Part D covers Medicare prescriptions only.
What is Mariko Ishiyama, D.O's MIPS final score?
The 2023 MIPS final score is 85.7 of 100, reported for the practice group. The average among 454,083 clinicians with a measured score was 83.5.
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.