Guy A. Weiss, M.D.
NPI 1598084030ActiveIndividual· Internal Medicine, Gastroenterology· Buffalo, NY
Internal Medicine, Gastroenterology (M.D.) with The Regents of the University of California, practicing in Buffalo, New York. Their prescriptions cost Medicare Part D more than their services did: $204,941 for 547 claims, against $87,894 paid for services in 2024. Genzyme Corporation was the largest of 4 companies reporting payments in 2025, $648.92 in all, mostly food and beverage. Lists Ronald Reagan UCLA Medical Center and 1 other hospital as hospital affiliations.
Overview
| NPI | 1598084030 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | May 24, 2010 |
| Last updated in NPPES | Aug 3, 2020 |
| Certified by provider | Aug 3, 2020 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Gastroenterology Primary | 207RG0100X | A125480 | CA |
| Student in an Organized Health Care Education/Training Program | 390200000X | — | — |
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 - Gastroenterology (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 407 |
|---|---|
| Services billed | 966 across 49 procedure codes |
| Paid by Medicare | $87,894 |
Part D prescriptions in 2024
| Prescriptions (claims) | 547 · 821 30-day fills |
|---|---|
| Patients | 174 |
| Total drug cost | $204,941 |
| Generic share | 60% of claims |
Education and affiliations
| Graduation year | 2010 |
|---|---|
| Medicare specialty | Gastroenterology |
| Secondary specialties | Internal Medicine |
| Telehealth | Offers telehealth |
Medical group
- The Regents of the University of CaliforniaSanta Monica, CA · 1,462 clinicians
Hospital affiliations
- Ronald Reagan UCLA Medical CenterLos Angeles, CA
- Santa Monica - UCLA Med Ctr & Orthopaedic HospitalSanta Monica, CA
Industry payments (Open Payments)
- 2025$648.92 · 14 payments from 4 companies
- 2024$6,706 · 29 payments from 4 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Genzyme Corporation | $339.09 | 7 |
| Ardelyx, Inc. | $169.45 | 5 |
| Abbvie Inc. | $125.62 | 1 |
| Regeneron Pharmaceuticals, Inc. | $14.76 | 1 |
What the 2025 payments were for
- Food and Beverage$648.92 · 14 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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