Steven Siwei Yu, MD
NPI 1659643682ActiveIndividual· Internal Medicine, Hematology & Oncology· Fountain Valley, CA
Internal Medicine, Hematology & Oncology (MD) in Fountain Valley, California, trained at Medical University of South Carolina College of Medicine (class of 2011). Their prescriptions cost Medicare Part D more than their services did: $3,080,431 for 1,022 claims, against $827,834 paid for services in 2024. Merck Sharp & Dohme LLC was the largest of 58 companies reporting payments in 2025, $6,462 in all, mostly food and beverage.
Overview
| NPI | 1659643682 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Feb 7, 2012 |
| Last updated in NPPES | May 21, 2025 |
| Certified by provider | May 21, 2025 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Hematology & Oncology Primary | 207RH0003X | A122462 | 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 - Hematology/Oncology (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 202 |
|---|---|
| Services billed | 45,378 across 73 procedure codes |
| Paid by Medicare | $827,834 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,022 · 1,562 30-day fills |
|---|---|
| Patients | 185 |
| Total drug cost | $3,080,431 |
| Generic share | 59% of claims |
Education and affiliations
| Medical school | Medical University of South Carolina College of Medicine |
|---|---|
| Graduation year | 2011 |
| Medicare specialty | Hematology/Oncology |
| Secondary specialties | Internal Medicine |
| Telehealth | Offers telehealth |
Medical group
- Los Angeles Hematology-Oncology Medical GroupVan Nuys, CA · 50 clinicians
Hospital affiliations
- Hoag Memorial Hospital PresbyterianNewport Beach, CA
- Memorialcare Orange Coast Medical CenterFountain Valley, CA
- Uci Health-OrangeOrange, CA
Industry payments (Open Payments)
- 2025$6,462 · 274 payments from 58 companies
- 2024$6,328 · 272 payments from 49 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Merck Sharp & Dohme LLC | $507.67 | 18 |
| Astrazeneca Pharmaceuticals LP | $461.95 | 20 |
| Novartis Pharmaceuticals Corporation | $365.28 | 14 |
| Janssen Biotech, Inc. | $344.18 | 14 |
| Daiichi Sankyo Inc. | $262.97 | 10 |
What the 2025 payments were for
- Food and Beverage$6,462 · 274 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 27 hematologist-oncologists in Fountain Valley · All hematologist-oncologists in California