MARIKO ISHIYAMA D.O
NPI 1952662991
Hospitalist in Modesto, CA
About Mariko Ishiyama D.o NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
MARIKO ISHIYAMA D.O (NPI 1952662991) is an individual hospitalist provider in Modesto, California, licensed in California (12904) and active in the NPI registry since June 2012. She is enrolled in Medicare PECOS and is a graduate of Other (2012).
NPPES Registry Identity
Specialties & Licenses 2
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Mariko Ishiyama D.o is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
4Medicare enrollment records show Mariko Ishiyama reassigns Medicare billing to 4 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Modesto, CA 95350
- Reassigned Medicare billing, California enrollment
- 176 clinicians in this Medicare group
Manteca, CA 95336
- Reassigned Medicare billing, California enrollment
- 962 clinicians in this Medicare group
Walnut Creek, CA 94598
- Reassigned Medicare billing, California enrollment
- 810 clinicians in this Medicare group
Walnut Creek, CA 94597
- Reassigned Medicare billing, California enrollment
- 650 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 3
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 95350 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
Reported Quality Measures
Other Providers at the Same Location NPPES 20
Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.
MODESTO, CA 95350
MODESTO, CA 95350
Frequently Asked Questions NPPES & CMS
Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.
What is Mariko Ishiyama's NPI number?
The NPI number for Mariko Ishiyama is 1952662991. It was assigned to this individual provider in the NPPES registry on June 6, 2012.
Where is Mariko Ishiyama located?
Mariko Ishiyama practices at 1441 Florida Ave, Modesto, CA 95350. The listed phone number is (209) 576-3525.
What is Mariko Ishiyama's specialty?
The primary specialty registered for this NPI is Hospitalist with taxonomy code 208M00000X.
Is Mariko Ishiyama enrolled in Medicare?
Yes. Mariko Ishiyama is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Mariko Ishiyama's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Mariko Ishiyama reassigns Medicare benefits to 4 organizations: Hospitalists Of Modesto Medical Group Inc (Modesto, CA), Galen Inpatient Physicians, PC (Manteca, CA), John Muir Trauma Physicians Billing Service (Walnut Creek, CA) and John Muir Physician Network (Walnut Creek, CA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Mariko Ishiyama's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
When was this NPI record last updated?
The NPPES record for Mariko Ishiyama was last updated on August 14, 2024. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.
# Mariko Ishiyama, D.O · NPI 1952662991
Hospitalist physician in Modesto, California. Individual provider, active in the CMS NPPES registry since June 6, 2012.
## Identity
- **NPI:** 1952662991 (Entity type: Individual)
- **Enumerated:** June 6, 2012
- **Primary specialty:** Hospitalist · taxonomy 208M00000X
- **State license:** 12904 (California)
- **Sole proprietor:** Yes
## Practice location
- **Address:** 1441 FLORIDA AVE, Modesto, CA 95350-4404
- **Phone:** (209) 576-3525
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 4 organizations under Medicare reassignment (form CMS-855R): Hospitalists Of Modesto Medical Group Inc (NPI 1821190711, Modesto, CA); Galen Inpatient Physicians, PC (NPI 1689320459, Manteca, CA); John Muir Trauma Physicians Billing Service (NPI 1962551861, Walnut Creek, CA); John Muir Physician Network (NPI 1841407665, Walnut Creek, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2012
## Record status
- **NPPES last updated:** August 14, 2024
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Source: [NPI Profile](https://npiprofile.com/npi/1952662991) · Data from the CMS NPPES public registry.