William P. Mustas, P.A.
NPI 1629080932ActiveIndividual· Physician Assistant· Waukesha, WI
Physician Assistant (P.A.) with Los Alamos Physician Practices LLC, practicing in Waukesha, Wisconsin. Their prescriptions cost Medicare Part D more than their services did: $101,116 for 628 claims, against $6,252 paid for services in 2024. Abbvie Inc. was the largest of 6 companies reporting payments in 2025, $134.26 in all, mostly food and beverage. Lists Los Alamos Medical Center as a hospital affiliation.
Overview
| NPI | 1629080932 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | P.A. |
| Sole proprietor | Yes |
| NPI issued | Aug 13, 2006 |
| Last updated in NPPES | Sep 18, 2024 |
| Certified by provider | Sep 18, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Physician Assistant Primary | 363A00000X | 1307 | 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 - Physician Assistant (NM); Practitioner - Physician Assistant (WI) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 95 |
|---|---|
| Services billed | 683 across 15 procedure codes |
| Paid by Medicare | $6,252 |
Part D prescriptions in 2024
| Prescriptions (claims) | 628 · 1,117 30-day fills |
|---|---|
| Patients | 230 |
| Total drug cost | $101,116 |
| Generic share | 79% of claims |
Education and affiliations
| Graduation year | 2000 |
|---|---|
| Medicare specialty | Physician Assistant |
Medical group
- Los Alamos Physician Practices LLCLos Alamos, NM · 20 clinicians
Hospital affiliation
- Los Alamos Medical CenterLos Alamos, NM
Industry payments (Open Payments)
- 2025$134.26 · 6 payments from 6 companies
- 2024$603.70 · 30 payments from 9 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Abbvie Inc. | $26.93 | 1 |
| Novartis Pharmaceuticals Corporation | $26.89 | 1 |
| Olympus America Inc. | $22.78 | 1 |
| Merck Sharp & Dohme LLC | $20.15 | 1 |
| Astellas Pharma US Inc | $19.74 | 1 |
What the 2025 payments were for
- Food and Beverage$134.26 · 6 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 86 physician assistants in Waukesha · All physician assistants in Wisconsin