Greggory Gahn, MD
NPI 1720541147ActiveIndividual· Ophthalmology, Retina Specialist· Tucson, AZ
Ophthalmology, Retina Specialist (MD) in Tucson, Arizona, trained at University of Nevada School of Medicine (class of 2019). Their prescriptions cost Medicare Part D more than their services did: $18,880 for 431 claims, against $7,151 paid for services in 2024. Genentech USA, Inc. was the largest of 7 companies reporting payments in 2025, $7,291 in all, mostly consulting fees.
Overview
| NPI | 1720541147 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Apr 11, 2019 |
| Last updated in NPPES | Sep 9, 2026 |
| Certified by provider | Sep 9, 2026 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Ophthalmology, Retina Specialist Primary | 207WX0107X | 80326 | AZ |
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 - Ophthalmology (AZ); Practitioner - Ophthalmology (NV) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 46 |
|---|---|
| Services billed | 56 across 9 procedure codes |
| Paid by Medicare | $7,151 |
Part D prescriptions in 2024
| Prescriptions (claims) | 431 · 578 30-day fills |
|---|---|
| Patients | 179 |
| Total drug cost | $18,880 |
| Generic share | 43% of claims |
Education and affiliations
| Medical school | University of Nevada School of Medicine |
|---|---|
| Graduation year | 2019 |
| Medicare specialty | Ophthalmology |
Medical groups
- Plecha Durant Stanko Johnson and Cohen A Professional CorporationReno, NV · 4 clinicians
- Retina Specialists of Southern Arizona PLLCTucson, AZ · 3 clinicians
Hospital affiliations
- Northern Nevada Medical CenterSparks, NV
- Renown Regional Medical CenterReno, NV
Industry payments (Open Payments)
- 2025$7,291 · 41 payments from 7 companies
- 2024$855.61 · 27 payments from 8 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Genentech USA, Inc. | $6,556 | 20 |
| Astellas Pharma US Inc | $263.18 | 9 |
| Harrow Eye, LLC | $185.69 | 3 |
| Regeneron Healthcare Solutions, Inc. | $96.40 | 1 |
| Abbvie Inc. | $81.66 | 3 |
What the 2025 payments were for
- Consulting Fee$5,475 · 1 payment
- Food and Beverage$1,371 · 38 payments
- Travel and Lodging$444.49 · 2 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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