Mark A. Casillas Jr., M.D.
NPI 1245458082ActiveIndividual· Surgery· Knoxville, TN
Surgery (M.D.) with University Health System, Inc., practicing in Knoxville, Tennessee. In 2024 Medicare paid $69,072 for 166 patients, and Part D covered 308 of their prescriptions, 85% of them generic. Ethicon US, LLC was the largest of 9 companies reporting payments in 2025, $360.84 in all, mostly food and beverage. Lists University Health System, Inc and 1 other hospital as hospital affiliations.
Overview
| NPI | 1245458082 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | Yes |
| NPI issued | Apr 24, 2007 |
| Last updated in NPPES | Feb 4, 2014 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Surgery Primary | 208600000X | LP00968 | RI |
| Colon & Rectal Surgery | 208C00000X | 48676 | TN |
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 - Colorectal Surgery (Proctology) (TN) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 166 |
|---|---|
| Services billed | 440 across 85 procedure codes |
| Paid by Medicare | $69,072 |
Part D prescriptions in 2024
| Prescriptions (claims) | 308 · 327 30-day fills |
|---|---|
| Patients | 146 |
| Total drug cost | $10,392 |
| Generic share | 85% of claims |
Education and affiliations
| Graduation year | 2006 |
|---|---|
| Medicare specialty | Colorectal Surgery (Proctology) |
| Secondary specialties | General Surgery |
Medical group
- University Health System, Inc.Knoxville, TN · 522 clinicians
Hospital affiliations
- University Health System, IncKnoxville, TN
- Wellmont Holston Valley Medical CenterKingsport, TN
Industry payments (Open Payments)
- 2025$360.84 · 14 payments from 9 companies
- 2024$553.83 · 18 payments from 9 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Ethicon US, LLC | $63.55 | 2 |
| Baxter Healthcare | $62.00 | 2 |
| Acera Surgical, Inc. | $57.57 | 3 |
| Abbvie Inc. | $48.31 | 2 |
| Integra Lifesciences Corporation | $36.66 | 1 |
What the 2025 payments were for
- Food and Beverage$360.84 · 14 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 66 general surgeons in Knoxville · All general surgeons in Tennessee