Dat Manh Nguyen, M.D.
Internal Medicine (M.D.) in Westminster, California, licensed in CA, with an NPI issued in January 2009. In 2024 Medicare paid $202,779 for 173 patients, and Part D covered 2,547 of their prescriptions, 88% of them generic. Galderma Laboratories, L.P. was the largest of 4 companies reporting payments in 2025, $338.26 in all, mostly food and beverage. A record with the same name and state is on the OIG exclusion list; it carries no NPI, so check it before acting.
Overview
| NPI | 1871730895 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | Yes |
| NPI issued | Jan 13, 2009 |
| Last updated in NPPES | Jan 13, 2009 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | A36056 | CA |
Exclusion screening
Possible match: verify before acting. The OIG list has a record with the same name in California, but that record carries no NPI, so it may be a different person or business.
| Matched by | Name on OIG list | Exclusion type | Excluded since | Location |
|---|---|---|---|---|
| Name + state | Dat Tat Nguyen · Business Manager | 1128a1 | Jul 20, 1999 | San Diego, CA |
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | Possible (name) | See above |
| 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 - Internal Medicine (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 173 |
|---|---|
| Services billed | 4,306 across 34 procedure codes |
| Paid by Medicare | $202,779 |
Part D prescriptions in 2024
| Prescriptions (claims) | 2,547 · 4,990 30-day fills |
|---|---|
| Patients | 238 |
| Total drug cost | $209,391 |
| Generic share | 88% of claims |
Education and affiliations
| Graduation year | 1975 |
|---|---|
| Medicare specialty | Internal Medicine |
Industry payments (Open Payments)
- 2025$338.26 · 5 payments from 4 companies
- 2024$146.45 · 2 payments from 2 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Galderma Laboratories, L.P. | $269.09 | 2 |
| Otsuka America Pharmaceutical, Inc. | $28.53 | 1 |
| Astrazeneca Pharmaceuticals LP | $24.16 | 1 |
| Xeris Pharmaceuticals, Inc. | $16.48 | 1 |
What the 2025 payments were for
- Food and Beverage$338.26 · 5 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 74 internal medicine physicians in Westminster · All internal medicine physicians in California