Zachary Gerard O'Leary, PA-C
NPI 1083298178ActiveIndividual· Physician Assistant· Castro Valley, CA
Physician Assistant (PA-C) in Castro Valley, California, trained at Stanford University School of Medicine (class of 2021). Their prescriptions cost Medicare Part D more than their services did: $467,624 for 5,711 claims, against $28,170 paid for services in 2024.
Overview
| NPI | 1083298178 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | PA-C |
| Sole proprietor | No |
| NPI issued | May 6, 2021 |
| Last updated in NPPES | Nov 28, 2023 |
| Certified by provider | Nov 28, 2023 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Physician Assistant Primary | 363A00000X | PA59454 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Not in the public enrollment file of Oct 1, 2026 |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 131 |
|---|---|
| Services billed | 327 across 20 procedure codes |
| Paid by Medicare | $28,170 |
Part D prescriptions in 2024
| Prescriptions (claims) | 5,711 · 14,234 30-day fills |
|---|---|
| Patients | 1,230 |
| Total drug cost | $467,624 |
| Generic share | 89% of claims |
Education and affiliations
| Medical school | Stanford University School of Medicine |
|---|---|
| Graduation year | 2021 |
| Medicare specialty | Physician Assistant |
| Telehealth | Offers telehealth |
Hospital affiliations
- Stanford Health CareStanford, CA
- Stanford Health Care Tri-ValleyPleasanton, CA
Industry payments (Open Payments)
None reported for 2025 or 2024.
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 27 physician assistants in Castro Valley · All physician assistants in California