Thomas G. Ahn, MD
NPI 1669556866ActiveIndividual· Internal Medicine· Los Angeles, CA
Internal Medicine (MD) in Los Angeles, California, trained at Virginia Commonwealth University, School of Medicine (class of 1979). Their prescriptions cost Medicare Part D more than their services did: $931,194 for 5,061 claims, against $175,292 paid for services in 2024. Abbvie Inc. was the largest of 29 companies reporting payments in 2025, $2,565 in all, mostly food and beverage.
Overview
| NPI | 1669556866 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | Yes |
| NPI issued | Oct 24, 2006 |
| Last updated in NPPES | Dec 14, 2025 |
| Certified by provider | Dec 14, 2025 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | G61939 | CA |
| Internal Medicine, Endocrinology, Diabetes & Metabolism | 207RE0101X | G61939 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Oct 9, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 10, 2026 | No match | — |
| New York OMIG · Nov 10, 2026 | No match | — |
| Ohio Medicaid · Nov 10, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 10, 2026 | No match | — |
| Washington HCA · Nov 10, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Endocrinology (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 437 |
|---|---|
| Services billed | 9,480 across 60 procedure codes |
| Paid by Medicare | $175,292 |
Part D prescriptions in 2024
| Prescriptions (claims) | 5,061 · 10,840 30-day fills |
|---|---|
| Patients | 459 |
| Total drug cost | $931,194 |
| Generic share | 73% of claims |
Education and affiliations
| Medical school | Virginia Commonwealth University, School of Medicine |
|---|---|
| Graduation year | 1979 |
| Medicare specialty | Endocrinology |
Hospital affiliation
- Cedars-Sinai Medical CenterLos Angeles, CA
Industry payments (Open Payments)
- 2025$2,565 · 115 payments from 29 companies
- 2024$2,619 · 124 payments from 23 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Abbvie Inc. | $313.68 | 20 |
| Mannkind Corporation | $264.69 | 13 |
| Novo Nordisk Inc | $253.14 | 11 |
| Beta Bionics, Inc. | $206.11 | 5 |
| Ardelyx, Inc. | $201.54 | 10 |
What the 2025 payments were for
- Food and Beverage$2,565 · 115 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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