Tony S. Chang, MD
NPI 1831166990ActiveIndividual· Internal Medicine· Madison, WI
Internal Medicine (MD) in Madison, Wisconsin, trained at University of Wisconsin School of Medicine (class of 1995). Their prescriptions cost Medicare Part D more than their services did: $835,647 for 7,967 claims, against $48,432 paid for services in 2024.
Overview
| NPI | 1831166990 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Mar 7, 2006 |
| Last updated in NPPES | Jan 4, 2021 |
| Certified by provider | Jan 4, 2021 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | 42048 | WI |
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 - Internal Medicine (WI) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 265 |
|---|---|
| Services billed | 1,230 across 47 procedure codes |
| Paid by Medicare | $48,432 |
Part D prescriptions in 2024
| Prescriptions (claims) | 7,967 · 15,606 30-day fills |
|---|---|
| Patients | 470 |
| Total drug cost | $835,647 |
| Generic share | 85% of claims |
Education and affiliations
| Medical school | University of Wisconsin School of Medicine |
|---|---|
| Graduation year | 1995 |
| Medicare specialty | Internal Medicine |
Medical group
- University of Wisconsin Medical Foundation IncMadison, WI · 2,553 clinicians
Hospital affiliations
- Unitypoint Health - MeriterMadison, WI
- University of Wi Hospitals & Clinics AuthorityMadison, WI
Other facilities
- Interim Healthcare of WisconsinHome health agency · Madison, WI
- Agrace HospicecareHospice · Madison, WI
Industry payments (Open Payments)
None reported for 2025 or 2024.
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 417 internal medicine physicians in Madison · All internal medicine physicians in Wisconsin