James Ahn
NPI 1457594574 · Internal Medicine Physician · Chicago, IL
Enrolled with Medicare as Practitioner - Emergency Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
James Ahn is a Internal Medicine Physician provider in Chicago, IL (NPI 1457594574).
Provider details
- NPI number
- 1457594574
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Sex
- Male
- Sole proprietor
- No
- License
- 036125480 (IL)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
17 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
107 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) |
|---|---|---|
| Emergency Department Visit With High Level of Medical Decision Making99285 | 92 | $197 |
| Emergency Department Visit With Moderate Level of Medical Decision Making99284 | 15 | $136 |
Typical Medicare-allowed amounts for these services range $136–$197 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$26 across 1 record (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
- 2009-04-20
- Last updated
- 2022-10-24
Frequently asked questions
- What is James Ahn's NPI number?
- James Ahn's National Provider Identifier (NPI) is 1457594574, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is James Ahn's specialty?
- James Ahn is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is James Ahn located?
- James Ahn's practice location on file with NPPES is 5841 S Maryland Ave, Chicago, IL 60637-1443.
- What is James Ahn's phone number?
- The practice phone number listed in the NPPES registry for James Ahn is (888) 824-0200.
- Does James Ahn accept Medicare?
- James Ahn is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is James Ahn's NPI active?
- Yes — James Ahn's NPI (1457594574) is active in the NPPES registry as of the last update on 2022-10-24.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.