Gregory Sean Hadfield, PA-C
NPI 1285869966ActiveIndividual· Physician Assistant, Medical· Lakeport, CA
Physician Assistant, Medical (PA-C) with Eye Associates of Sebastopol Medical Group, practicing in Lakeport, California. 1,060 Medicare patients in 2024, $638,208 paid; nearly all of their 2,238 Part D prescriptions were generic (94%). Incyte Corporation was the largest of 5 companies reporting payments in 2025, $183.20 in all, mostly food and beverage. Lists Adventist Health Clearlake as a hospital affiliation.
Overview
| NPI | 1285869966 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | PA-C |
| Sole proprietor | No |
| NPI issued | May 24, 2009 |
| Last updated in NPPES | Sep 4, 2026 |
| Certified by provider | Sep 4, 2026 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Physician Assistant, Medical Primary | 363AM0700X | P-16311 | 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) | Enrolled Practitioner - Physician Assistant (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 1,060 |
|---|---|
| Services billed | 18,561 across 72 procedure codes |
| Paid by Medicare | $638,208 |
Part D prescriptions in 2024
| Prescriptions (claims) | 2,238 · 2,521 30-day fills |
|---|---|
| Patients | 599 |
| Total drug cost | $825,380 |
| Generic share | 94% of claims |
Education and affiliations
| Graduation year | 2001 |
|---|---|
| Medicare specialty | Physician Assistant |
Medical group
- Eye Associates of Sebastopol Medical GroupClearlake, CA · 7 clinicians
Hospital affiliation
- Adventist Health ClearlakeClearlake, CA
Industry payments (Open Payments)
- 2025$183.20 · 9 payments from 5 companies
- 2024$396.52 · 16 payments from 4 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Incyte Corporation | $66.13 | 3 |
| Abbvie Inc. | $56.97 | 3 |
| Novartis Pharmaceuticals Corporation | $32.30 | 1 |
| Pfizer Inc. | $15.19 | 1 |
| Organon LLC | $12.61 | 1 |
What the 2025 payments were for
- Food and Beverage$183.20 · 9 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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