Robert M. McCallum, MD
NPI 1134264427ActiveIndividual· Specialist· Tucson, AZ
Specialist (MD) with Tucson Gastroenterology Specialists, PC, practicing in Tucson, Arizona. Their prescriptions cost Medicare Part D more than their services did: $550,435 for 1,690 claims, against $73,646 paid for services in 2024. Janssen Biotech, Inc. was the largest of 19 companies reporting payments in 2025, $2,520 in all, mostly food and beverage. Lists Tucson Medical Center as a hospital affiliation.
Overview
| NPI | 1134264427 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Feb 21, 2007 |
| Last updated in NPPES | Feb 15, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Specialist Primary | 174400000X | 30996 | AZ |
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 (AZ) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 378 |
|---|---|
| Services billed | 841 across 19 procedure codes |
| Paid by Medicare | $73,646 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,690 · 2,386 30-day fills |
|---|---|
| Patients | 871 |
| Total drug cost | $550,435 |
| Generic share | 80% of claims |
Education and affiliations
| Graduation year | 1988 |
|---|---|
| Medicare specialty | Gastroenterology |
Medical group
- Tucson Gastroenterology Specialists, PCTucson, AZ · 6 clinicians
Hospital affiliation
- Tucson Medical CenterTucson, AZ
Industry payments (Open Payments)
- 2025$2,520 · 128 payments from 19 companies
- 2024$1,783 · 92 payments from 19 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Janssen Biotech, Inc. | $391.35 | 17 |
| Abbvie Inc. | $323.08 | 19 |
| Takeda Pharmaceuticals U.S.A., Inc. | $259.59 | 11 |
| Pfizer Inc. | $248.57 | 15 |
| Aimmune Therapeutics, Inc. | $202.07 | 16 |
What the 2025 payments were for
- Food and Beverage$2,520 · 128 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 144 Specialist providers in Tucson · All Specialist providers in Arizona