Gordon Koon-Man Mak, M.D.
NPI 1447330725ActiveIndividual· Internal Medicine, Pulmonary Disease· Stanford, CA
Internal Medicine, Pulmonary Disease (M.D.) with Stanford Health Care and 1 other group, practicing in Stanford, California. Their prescriptions cost Medicare Part D more than their services did: $519,545 for 865 claims, against $17,374 paid for services in 2024. Bayer Healthcare Pharmaceuticals Inc. was the largest of 2 companies reporting payments in 2025, $278.99 in all, mostly consulting fees. Lists Peninsula Medical Center and 2 other hospitals as hospital affiliations.
Overview
| NPI | 1447330725 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | Oct 17, 2006 |
| Last updated in NPPES | Apr 12, 2024 |
| Certified by provider | Apr 12, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine, Pulmonary Disease Primary | 207RP1001X | A61568 | CA |
| Internal Medicine | 207R00000X | A61568 | CA |
| Internal Medicine, Critical Care Medicine | 207RC0200X | A61568 | 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 - Pulmonary Disease (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 159 |
|---|---|
| Services billed | 245 across 19 procedure codes |
| Paid by Medicare | $17,374 |
Part D prescriptions in 2024
| Prescriptions (claims) | 865 · 1,741 30-day fills |
|---|---|
| Patients | 136 |
| Total drug cost | $519,545 |
| Generic share | 37% of claims |
Education and affiliations
| Graduation year | 1995 |
|---|---|
| Medicare specialty | Pulmonary Disease |
| Secondary specialties | Critical Care (Intensivists), Internal Medicine |
| Telehealth | Offers telehealth |
Medical groups
- Stanford Health CareStanford, CA · 3,122 clinicians
- County of San MateoSan Mateo, CA · 310 clinicians
Hospital affiliations
- Peninsula Medical CenterBurlingame, CA
- San Mateo Medical CenterSan Mateo, CA
- Stanford Health CareStanford, CA
Industry payments (Open Payments)
- 2025$278.99 · 2 payments from 2 companies
- 2024$446.83 · 3 payments from 3 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Bayer Healthcare Pharmaceuticals Inc. | $200.00 | 1 |
| Sanofi-Aventis U.S. LLC | $78.99 | 1 |
What the 2025 payments were for
- Consulting Fee$200.00 · 1 payment
- Education$78.99 · 1 payment
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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