Mark Tan, M.D.
NPI 1083770580ActiveIndividual· Internal Medicine, Rheumatology· Smithtown, NY
Internal Medicine, Rheumatology (M.D.) in Smithtown, New York, trained at State University of New York at Buffalo School of Medicine (class of 1983). Their prescriptions cost Medicare Part D more than their services did: $3,082,792 for 1,327 claims, against $859,872 paid for services in 2024. Janssen Biotech, Inc. was the largest of 14 companies reporting payments in 2025, $3,078 in all, mostly food and beverage.
Overview
| NPI | 1083770580 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | Yes |
| NPI issued | Dec 29, 2006 |
| Last updated in NPPES | Jul 27, 2011 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Rheumatology Primary | 207RR0500X | 165674 | NY |
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 - Rheumatology (NY) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 393 |
|---|---|
| Services billed | 72,076 across 34 procedure codes |
| Paid by Medicare | $859,872 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,327 · 2,162 30-day fills |
|---|---|
| Patients | 289 |
| Total drug cost | $3,082,792 |
| Generic share | 60% of claims |
Education and affiliations
| Medical school | State University of New York at Buffalo School of Medicine |
|---|---|
| Graduation year | 1983 |
| Medicare specialty | Rheumatology |
| Secondary specialties | Internal Medicine |
| Telehealth | Offers telehealth |
Industry payments (Open Payments)
- 2025$3,078 · 127 payments from 14 companies
- 2024$3,014 · 142 payments from 13 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Janssen Biotech, Inc. | $849.05 | 24 |
| Abbvie Inc. | $589.22 | 21 |
| Amgen Inc. | $456.20 | 22 |
| Novartis Pharmaceuticals Corporation | $388.25 | 17 |
| Pfizer Inc. | $257.27 | 19 |
What the 2025 payments were for
- Food and Beverage$2,873 · 123 payments
- Education$205.37 · 4 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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