Thomas Ahn, MD
NPI 1669556866 · Internal Medicine Physician · Los Angeles, CA
Enrolled with Medicare as Practitioner - Endocrinology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Thomas Ahn, MD is a Internal Medicine Physician provider in Los Angeles, CA (NPI 1669556866).
Provider details
- NPI number
- 1669556866
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- G61939 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
9,264 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Insertion of Needle Into Vein for Collection of Blood Sample36415 | 673 | $9 |
| Blood Test, Thyroid Stimulating Hormone (tsh)84443 | 575 | $16 |
| Blood Test, Lipids (cholesterol and Triglycerides)80061 | 556 | $13 |
| Uric Acid Level, Blood84550 | 547 | $4 |
| Thyroxine (thyroid Chemical), Free84439 | 546 | $9 |
| Blood Test, Comprehensive Group of Blood Chemicals80053 | 544 | $10 |
| Lactate Dehydrogenase (enzyme) Level |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 97 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Levothyroxine Sodium | 367 | 91 |
| Rosuvastatin Calcium | 294 | 85 |
| Atorvastatin Calcium | 260 | 76 |
| Levothyroxine Sodiumbrand: Synthroid | 251 | 53 |
| Amlodipine Besylate | 149 | 41 |
| Zolpidem Tartrate | 132 | 28 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$2,596 across 119 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-10-24
- Last updated
- 2025-12-14
- Certified
- 2025-12-14
Frequently asked questions
- What is Thomas Ahn's NPI number?
- Thomas Ahn's National Provider Identifier (NPI) is 1669556866, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Thomas Ahn's specialty?
- Thomas Ahn is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Thomas Ahn located?
- Thomas Ahn's practice location on file with NPPES is 2080 Century Park E Ste 1410, Los Angeles, CA 90067-2017.
- What is Thomas Ahn's phone number?
- The practice phone number listed in the NPPES registry for Thomas Ahn is (310) 277-7600.
- Does Thomas Ahn accept Medicare?
- Thomas Ahn is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Thomas Ahn's NPI active?
- Yes — Thomas Ahn's NPI (1669556866) is active in the NPPES registry as of the last update on 2025-12-14.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.