Mark Nishiyama, MD
NPI 1033279849ActiveIndividual· Obstetrics & Gynecology· Centralia, WA
Obstetrics & Gynecology (MD) in Centralia, Washington, trained at Loma Linda University School of Medicine (class of 1987). 80 Medicare patients in 2024, $13,120 paid; nearly all of their 257 Part D prescriptions were generic (90%). Optumhealth Care Solutions, LLC was the largest of 6 companies reporting payments in 2025, $104.37 in all, mostly food and beverage.
Overview
| NPI | 1033279849 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Dec 11, 2006 |
| Last updated in NPPES | Jun 23, 2021 |
| Certified by provider | Jun 23, 2021 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Obstetrics & Gynecology Primary | 207V00000X | MD00039478 | WA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 10, 2026 | No match | — |
| New York OMIG · Nov 10, 2026 | No match | — |
| Ohio Medicaid · Nov 10, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 10, 2026 | No match | — |
| Washington HCA · Nov 10, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Obstetrics/Gynecology (WA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 80 |
|---|---|
| Services billed | 208 across 26 procedure codes |
| Paid by Medicare | $13,120 |
Part D prescriptions in 2024
| Prescriptions (claims) | 257 · 421 30-day fills |
|---|---|
| Patients | 91 |
| Total drug cost | $13,204 |
| Generic share | 90% of claims |
Education and affiliations
| Medical school | Loma Linda University School of Medicine |
|---|---|
| Graduation year | 1987 |
| Medicare specialty | Obstetrics/Gynecology |
Medical group
- Providence Health and Services WashingtonOlympia, WA · 475 clinicians
Hospital affiliation
- Providence Centralia HospitalCentralia, WA
Industry payments (Open Payments)
- 2025$104.37 · 6 payments from 6 companies
- 2024$410.62 · 20 payments from 4 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Optumhealth Care Solutions, LLC | $21.70 | 1 |
| Sage Therapeutics, LLC | $20.43 | 1 |
| Smith+nephew, Inc. | $19.16 | 1 |
| Hologic Sales and Service, LLC | $16.62 | 1 |
| Vertex Pharmaceuticals Incorporated | $16.10 | 1 |
What the 2025 payments were for
- Food and Beverage$104.37 · 6 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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