William Tsai, D.O.
NPI 1285620443ActiveIndividual· Family Medicine· Upland, CA
Family Medicine (D.O.) with William Tsai, D.O., Inc, practicing in Upland, California. Their prescriptions cost Medicare Part D more than their services did: $1,103,209 for 10,223 claims, against $48,653 paid for services in 2024. Novo Nordisk Inc was the largest of 14 companies reporting payments in 2025, $817.16 in all, mostly food and beverage. Lists San Antonio Regional Hospital as a hospital affiliation.
Overview
| NPI | 1285620443 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | D.O. |
| Sole proprietor | No |
| NPI issued | Sep 23, 2005 |
| Last updated in NPPES | Apr 24, 2024 |
| Certified by provider | Apr 24, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Family Medicine Primary | 207Q00000X | 20A7115 | CA |
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 - Family Practice (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 104 |
|---|---|
| Services billed | 760 across 15 procedure codes |
| Paid by Medicare | $48,653 |
Part D prescriptions in 2024
| Prescriptions (claims) | 10,223 · 18,353 30-day fills |
|---|---|
| Patients | 506 |
| Total drug cost | $1,103,209 |
| Generic share | 86% of claims |
Education and affiliations
| Graduation year | 1996 |
|---|---|
| Medicare specialty | Family Practice |
| Telehealth | Offers telehealth |
Medical group
- William Tsai, D.O., IncUpland, CA · 2 clinicians
Hospital affiliation
- San Antonio Regional HospitalUpland, CA
Other facilities
- Bristol Hospice - Inland Valley LLCHospice · Ontario, CA
- Caring Hands Palliative & Hospice IncHospice · Rancho Cucamonga, CA
- Chino Valley Health Care CenteNursing home · Pomona, CA
- Montclair Manor Care CenterNursing home · Montclair, CA
Industry payments (Open Payments)
- 2025$817.16 · 36 payments from 14 companies
- 2024$1,291 · 52 payments from 22 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Novo Nordisk Inc | $157.80 | 6 |
| Lilly USA, LLC | $111.69 | 5 |
| Salix Pharmaceuticals, A Division of Bausch Health US, LLC | $88.71 | 5 |
| Amgen Inc. | $82.28 | 4 |
| Novartis Pharmaceuticals Corporation | $69.31 | 3 |
What the 2025 payments were for
- Food and Beverage$817.16 · 36 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 72 family medicine physicians in Upland · All family medicine physicians in California