Theresa K. Hayssen, MD
NPI 1265412365ActiveIndividual· Colon & Rectal Surgery· Brookfield, WI
Colon & Rectal Surgery (MD) in Brookfield, Wisconsin, trained at Southern Illinois University School of Medicine (class of 1992). In 2024 Medicare paid $32,013 for 98 patients, and Part D covered 131 of their prescriptions, 77% of them generic. Intuitive Surgical, Inc. reported $591.93 in payments in 2025, mostly food and beverage.
Overview
| NPI | 1265412365 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Jan 17, 2006 |
| Last updated in NPPES | Feb 10, 2015 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Colon & Rectal Surgery Primary | 208C00000X | 39624 | 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 - General Surgery (WI) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 98 |
|---|---|
| Services billed | 211 across 45 procedure codes |
| Paid by Medicare | $32,013 |
Part D prescriptions in 2024
| Prescriptions (claims) | 131 · 131 30-day fills |
|---|---|
| Patients | 85 |
| Total drug cost | $5,532 |
| Generic share | 77% of claims |
Education and affiliations
| Medical school | Southern Illinois University School of Medicine |
|---|---|
| Graduation year | 1992 |
| Medicare specialty | General Surgery |
Medical group
- Ascension Medical Group-Southeast Wisconsin IncBrookfield, WI · 545 clinicians
Hospital affiliations
- Ascension Se Wisconsin HospitalMilwaukee, WI
- Ascension St Francis HospitalMilwaukee, WI
Industry payments (Open Payments)
- 2025$591.93 · 6 payments from 1 company
- 2024$33.81 · 1 payment from 1 company
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Intuitive Surgical, Inc. | $591.93 | 6 |
What the 2025 payments were for
- Food and Beverage$435.53 · 3 payments
- Travel and Lodging$156.40 · 3 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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